DMM Victor 98A+



This is one of Victors better models (189W looks to be a more advanced model of the same meter).



The box for the meter is a brown cardboard box, that is very practical for shipping.



The box contained the meter, probes, a usb cable, a calibration certificate and a DVD with manual in Chinese and software.
It is possible to download a manual from Victor, but it do not match the meter.





The probe is fairly standard with tip covers and the usual rating of CAT II 1000V without covers and CAT III 1000V / CAV IV 600V with covers.



The meter is heavy enough to be standing while turning the range switch or pressing buttons.







The two black “screws” are used to open the meter, but the sleeve must be removed first.

















The calibration certificate is on multiple pages and show how well the meter matches the calibration reference.



Display



All the segments on the display, as usual not all of them are used.
The display has two secondary displays and a bargraph where it can show maximum range.



A typical measurement without extra function activated, the bargraph shows that the range is “200”.



Activating max/min and selected average.



When measuring temperature the secondary display shows sensor value and reference temperature.



The dBm display



AC+DC is very nice with both AC and DC voltage displayed.



Logging mode, the meter will save a reading each second (It will also beep each second).



Capacitance mode, with no capacitor it shows OL, maybe due to a -0.1nF offset in the range. This prevents using the REL button to eliminate the offset.

Secondary display functions (After / is secondary values):

• REL: relative or percent/absolute/reference
  
• Auto-hold: Held value/Current value
  
• dB: dBm/voltage/impedance
  
• min/max: max/absolute/time since start of min/max
  
• AC-frequency: Frequency/voltage or duty cycle (This is valid for both voltage and current)
  
• Frequency: Frequency/duty-cycle
  
• AC+DC: AC+DC/AC/DC (This is valid for both voltage and current)
  
• Thermocoupler temperature: Temperature/sensor mV/reference temp
  
• RTD Temperature: Temperature/sensor ohm
  
• Logging mode: value/Record number/time
  
• Save: value/Memory number
  
• MEM: value/Memory number
  

• Hold: Freeze the display. Using the yellow shift first activates auto-hold.
  
• MaxMin: Activate min/max function, press to select average, hold down to deactivate. In mem this will increment memory no.
  
• Peak: Activate peak capture, press to select minimum, hold down to deactivate. In mem this will decrement memory no.
  
• Range: Select manual range and change manual range.
  
• Yellow: Selected secondary function on HOLD and SAVE.
  
• Hz %: Select frequency in AC modes and AC+DC in DC modes.
  
• REL/CLR: Enable relative mode. In MEM this will clear SAVE or LOGGING memory.
  
• SAVE/Logging: Save to SAVE memory, Using the yellow shift will start logging to LOGGING memory, but only if it is empty. In MEM this is used to enable viewing of LOGGING memory.
  

• VAC: Show AC voltage, frequency, duty cycle and dB
  
• mVAC: Show AC millivoltage, frequency, duty cycle and dB
  
• VDC: Show DC voltage, AC+DC, AC and DC.
  
• mVDC: Show DC voltage, AC+DC, AC and DC. Thermocoupler temperature is also selected here.
  
• : Continuity and diode.
  
• : Resistance and RTD temperature.
  
• : Capacitance.
  
• uA: uA current DC, AC, frequency, duty cycle, AC+DC
  
• mA: mA current DC, AC, frequency, duty cycle, AC+DC
  
• A: A current DC, AC, frequency, duty cycle, AC+DC
  
• MEM: View SAVE memory, press yellow shift and LOGGING to view LOGGING memory.
  

• A: High current
  
• mAuA: The lower current ranges, the selector switch will change between two different shunts.
  
• CON: The common terminal for all ranges.
  
• xxx: All other ranges.
  

• Volt and frequency
  
  
  
  • At 1Vrms in AC frequency input range is from 15Hz to 10kHz (Higher voltage do not improve range)
    
  • At 1Vrms in frequency input range is from 3Hz to 5MHz (Higher voltage do not improve range)
    
  • At 1Vrms in frequency input the meter can handle a DC offset from -3V to at least +8V
    
  • Duty cycle works from 10% to 99% at 100kHz with 2Vpp in frequency input, precision is within 3.0
    
  • Duty cycle works from 10% to 99% at 10kHz with 2Vpp in frequency input, precision is within 0.2
    
  • Max/min changes between max/min?/average, the min? updates for each measurement and do not capture a value (It do not show minimum).
    
  • Max/min can be used on voltage AC/DC/AC+DC, ohm, temperature, frequency, current AC/DC
    
  • Max/min on VDC needs about 500ms to capture a voltage on DC with repeating pulses (min is not captured).
    
  • Peak changes between peak max and peak min, both works fine.
    
  • Peak can be used on voltage DC and current DC
    
  • Peak on VDC needs about 20ms to capture a voltage.
    
  • 1 VAC on AC input is 5% down at 1.3kHz
    
  • 1 VAC on DC+AC input is 5% down at 1.3kHz
    
  • In dBm the impedance is assumed to be 600ohm
    
  • Display will show high voltage symbol at 30VDC/VAC
    
  • Input impedance is 10..11Mohm on DC. AC and mVAC is a capacitor (Impedance is around 5Mohm).
    
  • mV DC range is high impedance up to around 2 volt where it slowly drops to 3kOhm
    
  • Hz input impedance is about 1Mohm up to around 12V where it drops to 2kOhm.
    
  • Over voltage protection is 1000VDC/750VAC
    
  
  
• Current
  
  
  
  • 220mA range has audible alarm at 200mA
    
  • 10A range has audible alarm at 10A
    
  • uAmA current is protected by a 0.2A/250V 5*20mm fuse.
    
  • 10A current is protected by a 10A/250V 6.2*24mm fuse (Holder will fit 6×30mm fuse).
    
  
  
• Ohm, Continuity, diode and capacitance
  
  
  
  • Ohm needs about 5s to measure 100ohm
    
  • Ohm is 2.5V open and 0.8mA shorted
    
  • RTD is 2.3V open and 0.2mA shorted
    
  • Continuity beeps when resistance is below 50ohm.
    
  • Continuity is very fast (below 10ms).
    
  • Continuity is 0.8V open and 0.3mA shorted
    
  • Diode range uses 3.2V, max. display is 2.1999V at 0.2mA, max. current is 0.2mA shorted.
    
  • 10uF takes about 5.5 seconds to measure.
    
  • 70000uF takes about 28 seconds to measure when staring in nF range, 10 seconds in mF range.
    
  • No rated overload protection
    
  
  
• Miscellaneous
  
  
  
  • Current consumption of meter is about 3mA to 4.5mA depending on range, 37mA with backlight.
    
  • Current consumption when off is about 3uA.
    
  • Meter works down to 2.4V where display is very faded, it turns off at 2.2V, battery symbol show at 4.0V.
    
  • Reading do not change with battery voltage.
    
  • Backlight is stable down to 3.3V, then it starts fading and is about off at 2.6V.
    
  • Internal temperature sensor is about 10°C off, this means a 10°C error on thermocoupler measurements.
    
  • Viewing angle is good.
    
  • Display updates around 2.5 times/sec
    
  • Display needs a couple of updates to show the correct value.
    
  • Bargraph updates faster than display.
    
  • Backlight turns off together with meter, not before.
    
  • Meter will automatic turn off after 10 minutes without any warning.
    
  • Standard probes cannot be fully seated.
    
  • Weight is 511g without accessories, but with sleeve and batteries.
    
  • Size is 206 × 97 × 50mm.
    
  
  
• Probes
  
  
  
  • Probe resistance 26mOhm for one.
    
  • Probe wire is soft and 100cm long.
    
  
  

• Range switch did initially not work fully, it had to be rotated a couple of times before it worked in all ranges.
  
• min/max is not working correctly.
  
• Internal temperature sensor is 10°C wrong, i.e. all thermocoupler measurements are 10°C wrong.
  
• It is a bit cheap not to include a thermocoupler with the meter.
  
• PC software do not work.
  
• Capacity range has a -0.1nF offset and REL do not work, because the meter is in overload.
  

DMM BSide ADM20



This is the one of the best BSide meters, it includes a computer connection.



The meter arrived in a cardboard box without any branding on it but the drawing nearly matches the meter.



Inside the box was a pouch with the meter and everything else.



This means the meter, two probes, a thermocoupler, a transistor tester adapter, a USB cable, a CD and a manual.





Probes are branded with BSide and rated for 1000V, CAT II without tip covers and CAT III with covers.
The cable is rated for 10A, but that is very optimistic with the resistance I have measured.



The plug is fully shrouded with short shroud.




A standard cheap thermocoupler with a two banana plugs.




The transistor test plug can also be used for thermocouplers.



The meter is heavy and the tilting bale can hold it while the range switch is used or the buttons is pressed.











Display



The above picture shows all the segments on the display, a few of them are not used.



Normal DC voltage with voltage and bargraph. The bragraph always goes to 60 for ranges with maximum at 99 it will be stuck at maximum from 60 and up.



The bargraph is included on most ranges, but there are some exception.



Functions



Buttons (Range selection and a few other are remembered):

• Range: Switch to manual range and select range, hold down to activate automatic ranging again.
  
• Hz %: Select frequency or duty cycle in AC voltage and AC current modes. In Hz mode it selected duty cycle.
  
• Rel/USB. A short press will remember current value and show further values relative to this, press again to disable. Holding it down will enable the usb interface.
  
• °C/°F: Change between Celsius and Fahrenheit in temperature mode.
  
• Func (Red): Select AC/DC and ohm/continuity/diode/capacitance
  
• Max/Min: Supposed to capture maximum and minimum values (Do not work reliable), it changes between max/min/max-min., hold down to disable.
  
• H: Freeze the display, press again to release. Hold down to turn on background light.
  

• Off: Meter is turned off.
  
• V: Measure DC and AC voltage, use Hz button for frequency and duty cycle.
  
• mV: Measure DC and AC millivolt, use Hz button for frequency and duty cycle.
  
• Hz%: Logical frequency and duty cycle, this has much higher bandwidth.
  
• : Resistance, continuity, diode and capacitance.
  
• Temp: Measure temperature with a thermocoupler.
  
• hFE: Transistor tester, requires the supplied adapter.
  
• uA: The uA range, use Hz button for frequency and duty cycle.
  
• mA: The mA range, use Hz button for frequency and duty cycle.
  
• A: The A range, , use Hz button for frequency and duty cycle.
  
• Off: Meter is turned off.
  

• A: High current, maximum current is 10A, this is also used for the hFE adapter
  
• mAuA: The lower current ranges, this is also used for the hFE adapter
  
• CON: The common terminal for all ranges.
  
• xxx: All other ranges.
  

• Volt and frequency
  
  
  
  • At 0.1Vrms frequency input (VAC) range is from 2Hz to 1kHz
    
  • At 1Vrms frequency input (VAC) range is from 2Hz to 33kHz
    
  • Frequency input (VAC) requires a zero crossing.
    
  • At 0.1Vrms logical frequency input (Hz) range is from 2Hz to 6MHz
    
  • At 1Vrms logical frequency input (Hz) range is from 2Hz to 46MHz
    
  • Logical frequency input (Hz) requires a zero crossing.
    
  • Duty cycle works from 2% to 99% at 100kHz with 1Vpp, precision is within 0.2
    
  • 1 VAC is 5% down at 2kHz (RMS will not work at the frequency).
    
  • Max/min probably needs about 350ms to capture a voltage, but do not work reliable.
    
  • Input impedance is 10-11Mohm on AC/mVAC/DC
    
  • mV DC has high input impedance up to about 2V
    
  • Frequency input has high input impedance up to about 2V
    
  • Rated overload protection on V ranges 1000VDC 750VAC
    
  
  
• Current
  
  
  
  • All current ranges has audible alarm when overloaded.
    
  • Overload protection in uA and mA: 0.6A/1000V 6.3×32mm fuse (The mounted fuse was 250V)
    
  • Overload protection in A: 10A/1000V 6.3×32mm fuse (The mounted fuse was 250V)
    
  
  
• Ohm, continuity, diode and capacitance
  
  
  
  • Ohm needs about 2.7s to measure 100ohm
    
  • Ohm is 1.0V open and 0.33mA shorted
    
  • Continuity is very fast (Below 10ms).
    
  • Continuity beeps when resistance is below 50ohm
    
  • Continuity is 1.0V open and 0.33mA shorted
    
  • Diode range uses 3.2V, max. display is 1.5V at 0.74mA, max. current is 1.4mA shorted
    
  • 10uF takes about 4.5 seconds to measure.
    
  • 70000uF takes about 7 seconds to measure.
    
  • Rated overload protection on V ranges 1000VDC 750VAC
    
  
  
• Miscellaneous
  
  
  
  • Current consumption of meter is 2mA-2.5mA, the high value is for AC modes (73mA with backlight, usb adds about 0.6mA)
    
  • Meter works down to 2.1V, at 2V it might reset and slightly below that turn off, battery symbol show at 4.7V.
    
  • The meter reading is stable down to about 3V, then it will show a few counts low (With 5V I got 10 count down to 2V).
    
  • Backlight is fades with battery voltage and is just about gone at 2.7V
    
  • The meter need a couple of updates before the reading is fully correct.
    
  • Viewing angle is good
    
  • Display updates around 4 times/sec
    
  • Bargraph updates at same rate as numbers
    
  • Backlight will turn off in 15 seconds
    
  • Will automatic turn power off in about 15 minutes
    
  • Standard probes fits into sockets on meter.
    
  • Weight is 458g without accessories, but with batteries.
    
  • Size is 194 × 93.4 × 54mm.
    
  
  
• Probes
  
  
  
  • Probe resistance 126mOhm for one.
    
  • Probe wire is a bit stiff and 100cm long.
    
  
  

Small Oscilloscope DANIU DSO188



This is a very small oscilloscope with a minimum of functions.

Official specifications:

• Analog band width: 1MHz
  
• Maximum real time sampling rate: 5MS/s
  
• Vertical sensitivity: 50 mV/div-200 V/div
  
• Horizontal time base range: 100mS/div-2uS/div
  
• Maximum input voltage: 40 V (1X probe), 800 V (10X probe)
  
• Storage depth: 40KB
  
• Input resistance: 1M
  
• ADC precision: 12bits
  
• Coupling mode: AC/DC
  
• Trigger mode: Auto
  
• Trigger edge: Ascending/descending edge
  
• External trigger voltage 0-40V
  
• Display: TFT color display
  
• Power supply: 250 mAh lithium battery
  
• Size: 57 × 34 × 11 mm
  
• Weight: 40 grams
  

• Time/div settings: 2us, 5.5us, 10us, 20us, 50us, 100us, 200us, 500us, 1ms, 2ms, 5ms, 10ms, 20ms, 50ms, 100ms
  
• Volt/div settings (1x): 50mV, 0.1V, 0.2V, 0.5V, 1V, 2V, 5V, 10V, 20V
  
• Volt/div settings (10x): 50V, 100V, 200V (Why no overlap with the lower voltages, this would be useful)
  
• Input impedance: 510kOhm for both AC & DC (This means it will not work with standard probes)
  
• AC coupling can show small AC voltage on large DC voltages, it adds a capacitor in series with the input.
  
• Input capacitance: 134pF (138pF in the 3 lowest voltage ranges). 10x do not change it.
  
• Current draw from battery when off: less than 0.01uA
  
• Current draw from battery when on: 106mA
  

DMM Mustool MT108T



This is a smaller meter that has a lot of ranges.





I got the meter in a brown cardboard box, the drawing mostly matches the meter.



It included the DMM, a pair of probes, a thermocoupler and a manual.





The probes has is rated for CAT III, but do not include the partial tip covers.



The shrouded plug is the slightly short variety.




A standard cheap thermocoupler.



The range switch is a bit difficult to use single handed when meter is on the tilting bale, it slides around.






There is a flashlight led on the front of the meter.


















Display



The above picture shows all the segments on the display.



Typical display during usage, it will show the number and what measurement is selected.



The NCV is the usual bars and the buzzer.



Functions



Buttons:

• Select (White): Select the ranges printed with yellow.
  
• Hold: Freezes the display, hold down for backlight.
  
• Range/Rel: Will disable auto range and change range, hold down to activate auto range. In capacity mode it will zero the reading.
  
• Max/min: Starts recording maximum and minimum value, press to select between max/min/disable. Hold down to turn the flashlight on/off.
  

• Off: Meter is turned off
  
• VAC: Show AC voltage, using the Select button to select frequency and duty cycle.
  
• VDC: Show DC voltage.
  
• : Resistance, diode, continuity, diode, capacitance, Fahrenheit, Celsius.
  
• Hz: Logical frequency and duty cycle (Use Select to change between them).
  
• A: Current DC and AC (Use Select to change between them).
  
• mA: Current DC and AC (Use Select to change between them).
  
• uA: Current DC and AC (Use Select to change between them).
  
• : Square wave output, use Select to select next frequency.
  
• NCV: Non-contact voltage or electric field detection.
  

• 10A: High current input
  
• COM: The common terminal for all ranges.
  
• xxx: All other ranges, including uA and mA.
  

• Volt and frequency
  
  
  
  • At 100mVrms in AC voltage frequency range is from 1.3Hz to 2.5kHz
    
  • At 2Vrms in AC voltage frequency range is from 1.3Hz to 70kHz
    
  • At 1Vrms in frequency input range is from 1.1Hz to 42MHz
    
  • At 1Vrms in frequency input the meter can handle a DC offset from -2.5V to +6.5V
    
  • Duty cycle do not work at 2V input due to the automatic offset compensation, it only shows the correct value shortly when duty cycle as away from 50%.
    
  • Duty cycle works from 1% to 99% at 100kHz with 4Vpp, precision is within 0.3 (Mostly 0.1).
    
  • Max/min needs about 150ms to capture a voltage with repeating pulses.
    
  • 1 VAC is 5% down at 2.3kHz (RMS will not work at the frequency).
    
  • Input impedance is 10..11Mohm on DC and AC
    
  • Frequency input is above 1Mohm up to around 1.5 volt, then the protection clamps to 3kOhm
    
  • Overload protection on DC is 1000VDC and 750VAC peak, except 6V range is 550V DC or AC peak.
    
  • Overload protection on AC is not rated.
    
  • Overload protection on frequency is 550VDC and AC peak, but meter may be damage at 250VAC peak (This is what the specifications says).
    
  
  
• Current
  
  
  
  • uAmA current is protected by a 0.63A/250V or 0.6A/250V 5×20mm glass fuse.
    
  • 10A current is protected by a 10A/250V 5×20mm ceramic fuse.
    
  • The 10A range has an audible alarm at 10A.
    
  • Current ranges must only be used up to 36VDC or 25VAC
    
  
  
• Ohm, Continuity, diode and capacitance
  
  
  
  • Ohm needs about 3.0s to measure 100ohm
    
  • Ohm is 1.1V open and 0.26mA shorted
    
  • Continuity is fast (About 20ms).
    
  • Continuity beeps when resistance is below 50ohm.
    
  • Continuity is 2.1V open and 0.26mA shorted
    
  • Diode range uses 4.0V, max. display is 3.300V at 0.25mA, max. current is 1.5mA shorted
    
  • 10uF takes about 2.5 seconds to measure.
    
  • 11000uF takes about 9.5 seconds to measure.
    
  • 70000uF takes about 9.5 seconds to measure.
    
  • Overload protection is 550V DC or AC peak
    
  
  
• Miscellaneous
  
  
  
  • Square wave frequencies supported: 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 4000, 5000
    
  • Current consumption of meter is 1.1 to 1.6mA depending on range (Mostly 1.6mA), with backlight it is up to 9.3mA, with both flashlight and backlight it is 13mA.
    
  • Meter works down to 2.2V where it turns off, battery symbol show at 2.4V.
    
  • Reading do changes when voltage is down to 2.4V, but it is less than 1% before meter turns off.
    
  • Backlight and flashlight changes with voltage and works down to the meter turns off.
    
  • The meter usual shows the correct value on the first display update.
    
  • Viewing angle is good, except from top.
    
  • Display updates around 3 times/sec
    
  • Backlight will automatic turn off in about 12 seconds.
    
  • Backlight has a hotspot in front of the minus sign.
    
  • Flashlight can be manually turn on/off and will turn off when the meter turns off.
    
  • Will automatic turn power off in about 17 minutes.
    
  • Standard probes cannot be pushed fully down.
    
  • Weight is 209g without accessories, but with rubber sleeve and batteries.
    
  • Size is 145 × 70 × 37mm with rubber sleeve.
    
  
  
• Probes
  
  
  
  • Probe resistance 46mOhm for one.
    
  • Probe wire is soft and 73cm long.
    
  
  

“Old McDonald had a knife E-I-E-I-O..”

———
There are a lot of people here, who combine flashaholism with knifemania (or whatever it`s named in English). I, personally, own pair of budget knives and that`s enough for my modest needs: cutting wires, opening parcels, getting smartphones from college kids etc. So, I definitely can be calm when I see all these “flash-sale! Flash-sale!’’ knife deals, they`re not really tempting for me. Nevertheless, when I saw NTK10, I was hypnotized by it`s unusual appearance. Stars gathered into lucky combination and i got it for review. So, here it is

NTK10 official page at Nitecore website.

PACKAGE AND APPEARANCE

NTK10 package is accurate black cardboard box. It has modest design, but that is the accurate, intentional modesty, not budget. Print is good and considering NTK10 as a gift, package`ll be of for it.

Inside, deep in black foam rubber lays the knife itself. Grey matte thing with unusual and attractive appearance. Ok, well, I have to be honest here. This design is attractive for me. My buddy says that design is not attractive at all. But he uses that multi-LEDs 50000lumens piece of junk from Ali as a headlamp. That speaks a lot about his taste IMO… -)

Let`s see it from all the angles.

Tail. Here we can see:
1) Lace for hanging this knife or attaching carabiner.
2) Sharp part as a glass breaker.
3) narrow slit to insert new blade.

Despite rectangular shape, grip is unexpectably convenient. AS chamfers are removed, the edges do not stick into the palm like it was, for example with one cheap knife that I once bought.
And as rear side is partly beveled, according to position of palm, it also adds a lot to comfort of grip. And grip is firm, even with gloves on. Really firm.

Down side is anatomically curved, fingers lay straight on it. Clip (removable) plays it`s role here as well. BTW, clip seems to be made of stainless still, not from Titanium.

Front side looks like animal head. And that doesn’t look like wretched work, typical for noname stuff, design here definitely harmonizes with overall appearance. Sharp nose can be used like glass breaker as well as sharp rear side.

Blade is, thanx, 100% available in any store. All the utility knives that I own use segment blades, the ones where you can break off blunt part of blade. Here you use CKB-2 blade. Razor sharp and quite thick, comparing to segment blade -1.2mm.

Blade move is long. I mean long for utility knife. If you fully release segment blade, it will easily get broken. CKB2 is much harder and can be used even when fully moved out.

There is a small fixator which you have to press, to unlock blade. IF you are right-handed guy, you`ll find it more convenient than in case you are like me, left-handed. Blade moves smoothly.

Ok, that`s blade – let`s cut thing. I did short video-review, there are alive video in the final part, you can see there how sharp this blade. And, again, it is razor sharp.

Just see this shaving of nail.

What else – It easily cuts paper. Just

I also tried to shave hand – thing which I never managed to do with my regular EDC knife, when I tested it sharpness.

Of course, it has it`s own disadvantages. Though blade is Japan made, good metal and stuff, you have to understand that there is no sense to sharpen it when it gets blunt (though you may try). You replace it with new one, that`s it. As pair of these blades cost like 2$, you simple can forget about this. This extra pair of blades takes almost no space.

OVERALL IMPRESSION.

Well, once that`s the utility knife – I have to judge it according to that fact. You cannot use this knife for a lot of works that fixed knife suits for – cutting bones etc . And, well – you shouldn’t. as that`s utility knife. But for it`s purposes it perfectly work. Office, home and repair work – that’s area when this knife will work perfectly.

At the same time, that`s utility knife with price of good regular one. Yes, it is Titanium and limited edition. It looks damn good to my taste, and feels comfortably in hand. It is convenient in work. But, I consider NTK10 to be more a gift and collectible thing for it`s price. But, well, which Ti model (no matter – knife, flashlight, tactical pen) is not that one? So in need of knife just for some repair work, I don’t think that NTK10 will come to your mind. But when you look for a gift for you friend who is involved in repair works or want to put in pocket something that will please your eye and stand out from other utility knives – that`s the one.

Finally, i`ve got no complaints about appearance, construction and functionality.

I would definitely like to see if Nitecore release some regular EDC knife in this model line. The start is good.

3rd and most recent model in Nitecore tactic pens model line.

NTP30 at Nitecore website

PACKAGE AND APPEARANCE

As i can see, concept of design, that Nitecore use, has 2 separate packages. Well known yellow-black for mass-market, for regular stuff. And pitch black for limited edition, expensive stuff. TM10K, Concept2, NTK10 and NTP30.

I like that design at all, and how it looks like for NTP30. The only thing that i`d change is material of package, that should be the same thick cardboard as of NTK10. Package of NTP30 is rather thin.

The orange tab deliberately contrasts with a strict and restrained blackness of package, illustrating the parts of the pen. Mostly senseless, but good looking part of package.

Well, here’s the pen itself from different angles. Gray, shiny, expensive and expensive looking (for tactical pen). I have some other tactical pens, but this definitely has the best appearance.

There is noteworthy detail of the design – a spring-loaded switch, partly similar to a gun bolt, that fact that Nitcore was brought into the promo-pics advantage. Bring it up – the carbide-voltframe spike of glass breaker comes out. You slightly push switch with your finger and it clicks, turning to the “pen mode”, and firing the writing unit forward. As a mass of primitive activities (f.e spinner) this switching goes into a flash of unconscious movements and it becomes frankly difficult to resist not to consltanly click this switch.

Here it is, closer look

The grip is excellent, the pen sits in your fingers like a glove. It is not too thick, like many tactical pens, where the emphasis on the tactical component leads to an increase in diameter. Here, in my opinion, on the contrary – the appearance and dimensions make it necessary in the first place to perceive the Nitecore NTP30 as a pen, and in the second, as a tactical one. And in many ways this is a plus. Here is an example. There are many lovers of tactical gear and all about it. And, by no means, not all of them have the opportunity to walk day to day in cargo pants, camouflage t-shirt and “5.11” baseball cap, having to be dressed in corporate camouflage of an office employee instead . And after some level, where people are already starting to pay attention to cufflinks-watches-pens, a common tactical pen spindle may look crooked and inappropriate, unlike the strict and neat NTP30. The latter in this respect, in my opinion, is flawless.

For the sake of justice, being comfortable for writing , in its combat position, the pen partly looses firmness of grip , comparing to the budget and purely tactical competitor. But that is exactly because of its relatively usual diameter. And not to the degree of inconvenience, no. Just some kind of ten-dollar thick “spindle” will be more grippy if you need to use tactical pen as a glass-breaker.

Well and, actually, as for the writing – everything is excellent here. The ink gel refill is well known and reliable Schneider one, which simply floats on the paper, leaving behind a black trace of ink. Writing is very convenient.

there is also a short video review here

OVERALL IMPRESSION

Nitecore ask for this model frankly a lot, about 120 bucks . But they do not offer in return any absurdity or incompleteness. NTP30 looks great and fits comfortably in your hand, It writes really smoothly and glass breaker can be used for self-defence and other similar needs.

In my opinion, as written above, NTP30 looks and feels more of a pen than a tactical. Because of this, it will not cause bewildered views, if used for its intended purpose in office or at business meeting . NTP30 is quite suitable as a pen that`ll fit any corporate dress-code. That`ll be a serious challeng for a lot other tactical pens on the market which looks more like a weapon.

Due to the price, being Titanium and limited-edition, I dont believe that NTP30 will face wide popularity – and that is no surpise. For the same reason, it will be a defintely good gift when it comes down to give a tactical pen as a gift, good looking titanium tactical pen, not budget price and cheap looking thing.

the only thing that i`d change, is package. It definetely should be solid cardboard box like NTK10`s one.

DMM UNI-T UT191T



This is a industrial grade DMM designed for electricians. This series has two versions E without temperature and T with temperature, this is the T version.





I got it in a retail box where the meter is very visible (It is covered by shaped plastic).



The box contained the meter, a pair of probes, a thermocoupler, a manual and a pouch.



Everything fits in the pouch.





Probes are branded UNI-T and rated for 20A, they have very low resistance and the 20A rating looks good enough.
With a tip cover they are CAT IV 600V or CAT III 1000V, without CAT II 1000V (This is fairly standard for probes).



The plugs are fully shrouded, but the shroud is a bit short




The thermocoupler has a 3 pin plug that fits into the meter, it will also fit other meters with the input terminals in line.



The meter is fairly heavy and the range switch easy to turn, this means it can easily be used with one hand, either lying flat or standing.



All the red plastic is slightly rubberized in feel including the range switch.
The red plastic works as bumpers from any direction.





The flashlight led and a hanger.






There was five screws to hold the battery cover



These marks is a good indication that the meter passes the CAT test.



Display



All the segments are shown during power on.



Typical display during usage, it will show the number and selected measurement



Functions



Buttons:

• Range: Select manual range and change range, hold down to reactivate automatic ranging (Hz and C is always auto).
  
• Max/min: Capture maximum and minimum values, it will change between max/min, bargraph will show actual value. Hold down to disable.
  
• Rel: Shows values relative to current value, will also select manual range. Press again to disable. Hold down to turn backlight off until next power cycle.
  
• Hz %: Show frequency and duty cycle in AC voltage and current ranges, in Hz mode it will select duty cycle. Hold down to turn flashlight on.
  
• Hold (Yellow): Will freeze the display reading, until pressed again.
  
• Select (Blue): Select DC/AC in mV and current modes, continuity, diode, capacitance in ohm mode, LPF in VAC and can also be used to show duty cycle in Hz mode. The actual selection is remembered when changing range or turning power off.
  

• LoZ: Low input impedance (300kOhm), range is always 600VAC.
  
• Off: Meter is turned off
  
• VAC: AC voltage with or without LPF (Low Pass Filter). It is possible to select Hz.
  
• VDC: DC voltage.
  
• mV: AC or DC milli volt, it is possible to select Hz in AC mode.
  
• : Ohm, capacitance, diode and continuity.
  
• Hz: Logical frequency input.
  
• °C °F: Temperature, use SELECT for Celsius or Fahrenheit
  
• uA: Micro ampere DC or AC, it is possible to select Hz in AC mode.
  
• mA: Milli ampere DC or AC, it is possible to select Hz in AC mode.
  
• A: Ampere DC or AC, it is possible to select Hz in AC mode.
  

• A: 20A current input.
  
• COM: The common terminal for all ranges.
  
• xxx: All other ranges, including uA and mA
  

• Volt and frequency
  
  
  
  • MilliVolt ranges remembers last AC/DC setting.
    
  • 1V AC readings is 5% down at 2kHz, rms will not work at that frequency
    
  • 7V AC readings is 5% down at 800Hz when LPF is active, rms will not work at that frequency
    
  • At 0.1Vrms ACV frequency range is from 2Hz to 2.5kHz
    
  • At 1Vrms ACV frequency range is from 1.1Hz to 30kHz
    
  • AC frequency requires a zero crossing.
    
  • Frequency input do not require a zero crossing and handles at least +/-9.8V offset at 0.1VAC.
    
  • At 0.1Vrms frequency input range is from 1.1Hz to 1.1MHz
    
  • Duty cycle works from 20% to 80% at 100kHz with 1Vpp, precision is within 2.0.
    
  • Duty cycle works from 1% to 99% at 100kHz with 4Vpp, precision is within 0.1.
    
  • Max/min needs about 380ms to capture a repeating voltage max, autorange is disabled when using this function.
    
  • Peak can only be selected in AC V and mV will capture a maximum in less than 0.2ms, but it may be 20% to high. The values captured are DC values.
    
  • Input impedance is 10-11Mohm on DC and AC
    
  • mVDC is high impedance up to about 2V where it drops to about 20kOhm, above 14V it will drop to 3kOhm
    
  • mVAC is the same, but capped by a 10MOhm resistor.
    
  • Frequency input is 10Mohm
    
  • LowZ is constant 300kOhm input impedance and is locked in 600VAC range.
    
  • Input protection is 600VDC/600VAC
    
  
  
• Current
  
  
  
  • 20A range has audible alarm above 10A
    
  • Current ranges each remember AC/DC settings.
    
  • 20A range is fused with a 11A/1000V 10×38mm fuse
    
  • mAuA range is fused with a 0.6A/600V 6.3×32mm fuse
    
  • Peak can be selected in AC.
    
  
  
• Ohm, continuity, diode and capacitance
  
  
  
  • Ohm needs about 2.8s to measure 100ohm
    
  • Ohm voltage is 1.0V open and 0.33mA shorted.
    
  • Continuity is very fast (less than 5ms).
    
  • Continuity beeps when resistance is below 50ohm.
    
  • Continuity is 1.0V open and 0.33mA shorted
    
  • Diode range uses 3.2V, max. display is 1.200V at 0.86mA, max. current is 1.4mA shorted
    
  • 10uF takes about 2.5 seconds to measure.
    
  • 11000uF takes about 6.5 seconds to measure.
    
  • Overload protection is 600V
    
  
  
• Miscellaneous
  
  
  
  • Current consumption of meter is 2.2 to 3mA (44mA with flashlight, 62mA with background light, max. is 100mA).
    
  • Display starts fading around 3.4V and is gone at 2.2V, battery symbol shows empty at 6.2V.
    
  • Readings will be correct until the display is faded.
    
  • Backlight and flashlight starts fading at 4V and is gone at 2.7V
    
  • Viewing angle is good
    
  • Display updates around 3 times/sec
    
  • Bargraph updates at same speed as display.
    
  • Backlight will automatic turn on when in dark surroundings
    
  • Flashlight will not turn off automatic, but turns off with the auto power off.
    
  • Will automatic turn power off in about 16 minutes.
    
  • Standard probes cannot be fully seated in the meter, but they do connect.
    
  • The meter usual need a few display update to before it display the value.
    
  • Weight is 441g without accessories, but with battery.
    
  • Size is 180 × 87.5 × 55.5mm
    
  
  
• Probes
  
  
  
  • Probe resistance 15mOhm for one, that is very low.
    
  • Probe wire are 79cm long and feels a bit stiff, probably due to the thickness.
    
  
  

DMM Borbede BD-168B



This is a smaller meter that has a lot of ranges. It exist in a A (Square wave out) and B (Measures temperature) version.





I got the meter in a brown cardboard box, the drawing mostly matches the meter.



It included the DMM, a pair of probes, a thermocoupler and a manual.





The probes is rated for CAT III, but do not include the partial tip covers.



The shrouded plug is the slightly short variety.




A standard cheap thermocoupler.



The range switch is a bit difficult to use single handed when meter is on the tilting bale, it slides around.





















Display



The above picture shows all the segments on the display, the square wave symbol is not used on this meter.



Typical display during usage, it will show the number and what measurement is selected.



The NCV is the usual bars and the buzzer.



Functions



Buttons:

• Select (Yellow): Select the ranges printed with yellow.
  
• Hold: Freezes the display, hold down for backlight.
  
• Range/Rel: Will disable auto range and change range, hold down to activate auto range. In capacity mode it will zero the reading.
  
• Max/min: Starts recording maximum and minimum value, press to select between max/min/disable. Hold down to turn the flashlight on/off.
  

• Off: Meter is turned off
  
• VAC: Show AC voltage, using the Select button to select frequency and duty cycle.
  
• VDC: Show DC voltage.
  
• : Resistance, diode, continuity, diode and capacitance.
  
• Hz: Logical frequency and duty cycle (Use Select to change between them).
  
• A: Current DC and AC (Use Select to change between them).
  
• mA: Current DC and AC (Use Select to change between them).
  
• uA: Current DC and AC (Use Select to change between them).
  
• Temp: Show temperature, use select to change between Fahrenheit and Celsius
  
• NCV: Non-contact voltage or electric field detection.
  

• 10A: High current input
  
• COM: The common terminal for all ranges.
  
• xxx: All other ranges.
  

• Volt and frequency
  
  
  
  • At 100mVrms in AC voltage frequency range is from 1Hz to 2.1kHz
    
  • At 2Vrms in AC voltage frequency range is from 1Hz to 60kHz
    
  • At 1Vrms in frequency input range is from 1Hz to 41MHz
    
  • At 1Vrms in frequency input the meter can handle a DC offset from -2.5V to +3.1V
    
  • Duty cycle do not work at 2V input due to the automatic offset compensation, it only shows the correct value shortly when duty cycle as away from 50%.
    
  • Duty cycle works from 1% to 99% at 100kHz with 4Vpp, precision is within 0.3 (Mostly 0.1).
    
  • Max/min needs about 150ms to capture a voltage with repeating pulses.
    
  • 1 VAC is 5% down at 2.3kHz (RMS will not work at the frequency).
    
  • Input impedance is 10..11Mohm on DC and AC
    
  • Frequency input is above 1Mohm up to around 1.5 volt, then the protection clamps to 3kOhm
    
  • Overload protection on DC is 1000VDC and 750VAC peak, except 6V range is 550V DC or AC peak.
    
  • Overload protection on AC is not rated.
    
  • Overload protection on frequency is 550VDC and AC peak, but meter may be damage at 250VAC peak (This is what the specifications says).
    
  
  
• Current
  
  
  
  • uAmA current is protected by a 0.63A/250V or 0.6A/250V 5×20mm glass fuse.
    
  • 10A current is protected by a 10A/250V 5×20mm ceramic fuse.
    
  • The 10A range has an audible alarm at 10A.
    
  • Current ranges must only be used up to 36VDC or 25VAC
    
  
  
• Ohm, Continuity, diode and capacitance
  
  
  
  • Ohm needs about 3.0s to measure 100ohm
    
  • Ohm is 1.1V open and 0.25mA shorted
    
  • Continuity is fast (About 20ms).
    
  • Continuity beeps when resistance is below 50ohm.
    
  • Continuity is 2.1V open and 0.25mA shorted
    
  • Diode range uses 4.0V, max. display is 3.300V at 0.25mA, max. current is 1.5mA shorted
    
  • 10uF takes about 2.5 seconds to measure.
    
  • 11000uF takes about 9.8 seconds to measure.
    
  • 70000uF takes about 9.8 seconds to measure.
    
  • Overload protection is 550V DC or AC peak
    
  
  
• Miscellaneous
  
  
  
  • Current consumption of meter is 1.3 to 1.7mA depending on range (Mostly 1.6mA), with backlight it is up to 8.4mA, with both flashlight and backlight it is 13mA.
    
  • Meter works down to 2.2V where it turns off, battery symbol show at 2.3V.
    
  • Reading do changes when voltage is down to 2.5V, but it is less than 1% before meter turns off.
    
  • Backlight and flashlight changes with voltage and works down to the meter turns off.
    
  • The meter usual shows the correct value on the first display update.
    
  • Viewing angle is good, except from top.
    
  • Display updates around 3 times/sec
    
  • Backlight will automatic turn off in about 12 seconds.
    
  • Backlight has a hotspot in front of the minus sign.
    
  • Flashlight can be manually turn on/off and will turn off when the meter turns off.
    
  • Will automatic turn power off in about 18 minutes.
    
  • Standard probes cannot be pushed fully down.
    
  • Weight is 209g without accessories, but with rubber sleeve and batteries.
    
  • Size is 145 × 70 × 37mm with rubber sleeve.
    
  
  
• Probes
  
  
  
  • Probe resistance 46mOhm for one.
    
  • Probe wire is soft and 73cm long.
    
  
  

DMM Mastech MS8340B



This is a high precision meter from Mastech with usb communication.



The box has an image of the small model in this series and specifications for both models on the back.



There was a lot of stuff in the box: The meter itself, probes, communication cable, CD, manual in Chinese and another in English with where small text. It is possible to find an English manual on the internet.





Probes are branded with Mastech and has removable tip covers. The CAT rating is the usual with CAT II without covers and CAT III & IV with covers.



The plug is fully shrouded and standard probe plug size.



The meter is heavy enough that the rotary switch and buttons can be used when it is on the tilting bale.












Display



The above picture shows all the segments on the display. Not all segments are used.



Typical display during usage, it will show the main number, a bargraph and what measurement is selected.



Functions



Buttons:

• Func: Select between the different modes on each position of the range switch.
  
• Hold: Freezes the display
  
• Rel: Shows values relative to current value
  
• Range: Manual range selection, hold down to return to automatic ranging.
  
• VAHz/%: Select frequency and duty cycle display in voltage and current modes, in frequency mode it will select duty cycle.
  
• Peak: Capture peak voltages
  
• Max/min: Select max/min mode, press to toggle between max/min/current, hold down to disable again.
  
• PC-Link: A short press will turn background light on, hold down to enable data output, this will also disable auto power off.
  

• Off: Meter is off
  
• V: VDC and VAC, use FUNC to select DC or AC.
  
• mV: Millivolt DC and AC, use FUNC to select DC or AC.
  
• : Resistance, continuity and diode
  
• : Capacitance
  
• Hz: Logical frequency and duty-cycle (use SELECT).
  
• uA: Microampere range, use FUNC to select DC or AC.
  
• mA: Milliampere range, use FUNC to select DC or AC.
  
• A: Ampere range, use FUNC to select DC or AC.
  

• A: High current, maximum current is 10A
  
• mAuA: The lower current ranges.
  
• CON: The common terminal for all ranges.
  
• xxx: All other ranges.
  

• Volt and frequency
  
  
  
  • At 1Vrms in VAC frequency range is from 10Hz to 100kHz
    
  • VAC/VDC frequency range requires a zero crossing.
    
  • At 0.1Vpp frequency input range is from 30Hz to 60kHz
    
  • At 1Vpp frequency input range is from 10Hz to 70MHz
    
  • At 0.1Vrms frequency input the meter can handle a DC offset from -0.3V to +0.3V
    
  • Duty cycle works from 5% to 95% at 100kHz with 2Vpp, precision is within 1.0.
    
  • 1 VAC is 5% down at 3.4kHz (RMS will not work at the frequency).
    
  • Max/min needs about 470ms to capture a voltage.
    
  • Max/min can show max/min/current value
    
  • Peak captures min and max values, it needs about 0.1ms to capture a voltage,
    
  • Input impedance is 8-9Mohm on DC/AC
    
  • Milli volt input impedance is 44Mohm up to about 3V where it drops to about 1MOhm
    
  • No specified overload protection
    
  
  
• Current
  
  
  
  • Overload protection in uA and mA: 0.25A/1000V 6.3×32mm fuse
    
  • Overload protection in A: 10A/1000V 10.3×38mm fuse
    
  • uA and mA range has audible alarm when current is too high
    
  
  
• Ohm, continuity, diode and capacitance
  
  
  
  • Ohm needs about 1.3s to measure 100ohm
    
  • Ohm is -0.4V open and -0.9mA shorted
    
  • Continuity is very fast (About 3ms).
    
  • Continuity beeps when resistance is below 30ohm
    
  • Continuity is -3.0V open and -0.9mA shorted
    
  • Diode range uses 2.8V, max. display is 1.8997V at 0.3mA, max. current is 0.95mA shorted, bargraph works up to 2.2V
    
  • 70000uF takes about 12 seconds to measure.
    
  • 10uF takes about 0.6 seconds to measure.
    
  • No specified overload protection
    
  
  
• Miscellaneous
  
  
  
  • Current consumption of meter is 1.6mA in capacity and Hertz, 2.4mA in most other ranges and 3.4mA when AC is selected. Backlight adds 10mA (PC-Link is insignificant).
    
  • Meter works down to 1.6V where it turns off, battery symbol show at 4.2V.
    
  • Reading changes when voltage is below 3.0V and is more than 10% wrong when meter turns off.
    
  • Backlight is stable down to about 4V, then it slow fades with voltage and is about off at 2.7V
    
  • Display may need a few update (1 to 3) before showing the correct value.
    
  • Viewing angle is acceptable, except from top
    
  • Display updates around 2 times/sec
    
  • Bargraph updates much faster than numbers (At least 15 times/sec)
    
  • Backlight will turn off in 58 seconds
    
  • Will automatic turn power off in about 15 minutes.
    
  • Standard probes fits in sockets, but are hard to press down.
    
  • Weight is 570g without accessories, but with batteries
    
  • Size is 204 × 102 × 57.5mm.
    
  
  
• Probes
  
  
  
  • Probe resistance 25mOhm for one.
    
  • Probe wire is soft and 100cm long.
    
  
  

DMM BTMeter BT-39C



This meter is from BTMeter and is the 39C mode, this looks to be the most advanced multimeter in the 39 series.




The meter arrived in a cardboard box, the branding is a label that is stuck on and on the back is a overview of the 39 series meters, including a capacitance and a LCR meter.



The box contained the meter, probes, thermocoupler, magnet, strap and a instruction sheet.



Probes are not branded and are specified for CAT III, this cannot be true with that much tip exposed.



The plug is fully shrouded but a bit short.




A standard cheap thermocoupler with two banana plugs.





The meter includes a strap, it can be used as a hanger, but can also make a look behind the meter, probably to strap it to an arm.




The magnet can be mounted on the back of the meter and used to secure it to metal.



The rotary switch and button can be used single handed when using the tilting bale.






















Display



The above picture shows all the segments on the display, a few of them are not used.



Usually the meter shows the selected range and the value.



Non contact voltage uses bars to show the electric field strength.



Add also a green and red led.



Functions



Buttons (Range selection and a few other are remembered):

• Select: Select AC/DC, ohm/continuity/diode/capacitance and Celsius/Fahrenheit
  
• Range: Switch to manual range and select range, hold down to activate automatic ranging again.
  
• Rel: Remember current value and show further values relative to this, press again to disable.
  
• Hold (Blue): Freeze the display, press again to release.
  
• Hz %: Select frequency in VAC and AAC modes, will also change between frequency and duty cycle.
  

• Off: Meter is turned off.
  
• V: Measure DC and AC voltage, use Hz button for frequency and duty cycle, mVAC can only be selected with RANGE button.
  
• : Resistance, continuity, diode and capacitance.
  
• °C/°F: Measure temperature with a thermocoupler, will display meter temperature when no thermocoupler is connected.
  
• Hz%: Logical frequency and duty cycle, this has much higher bandwidth.
  
• NCV: Non contact voltage or electric field detection.
  
• : Measure 1.5V battery with load
  
• : Measure 9V battery with load
  
• uA: The uA range, use Hz button for frequency and duty cycle.
  
• mA: The mA range, use Hz button for frequency and duty cycle.
  
• A: The A range, , use Hz button for frequency and duty cycle.
  

• A: High current, maximum current is 10A
  
• CON: The common terminal for all ranges.
  
• xxx: All other ranges.
  

• Volt and frequency
  
  
  
  • At 0.1Vrms frequency input (VAC) range is from 0.7Hz to 4kHz
    
  • At 1Vrms frequency input (VAC) range is from 0.5Hz to 15MHz
    
  • Frequency input (VAC) requires a zero crossing.
    
  • At 0.1Vrms logical frequency input (Hz) range is from 0.7Hz to 8MHz
    
  • At 1Vrms logical frequency input (Hz) range is from 0.5Hz to 39MHz
    
  • Logical frequency input (Hz) requires a zero crossing.
    
  • Duty cycle works from 1% to 99% at 100kHz with 1Vpp, precision is within 0.1
    
  • 1 VAC is 5% down at 2.4kHz (RMS will not work at the frequency).
    
  • Input impedance is 10-11Mohm on mVDC/mVAC/DC/AC
    
  • Frequency input has high input impedance up to about 1.5V then drops to about 2kOhm
    
  • 1.5V battery test uses a 30ohm resistor, i.e. the load is 50mA at 1.5V
    
  • 9V battery test uses a 90ohm resistor, i.e. the load is 10mA at 9V
    
  • Rated overload protection on V ranges 600VDC or VAC
    
  • Meter has audible alarm on over voltage.
    
  
  
• Current
  
  
  
  • Overload protection in uA and mA: 0.75A/250V 6×30mm fuse
    
  • Overload protection in A: 10A/250V 6×30mm fuse
    
  
  
• Ohm, continuity, diode and capacitance
  
  
  
  • Ohm needs about 2.7s to measure 100ohm
    
  • Ohm is 1.1V open and 0.26mA shorted
    
  • Continuity is fast (15ms).
    
  • Continuity beeps when resistance is below 50ohm
    
  • Continuity is 2.1V open and 0.26mA shorted
    
  • Diode range uses 4.0V, max. display is 3.3V at 0.27mA, max. current is 1.6mA shorted
    
  • 10uF takes about 2.3 seconds to measure.
    
  • 11000uF takes about 9.5 seconds to measure.
    
  • Rated overload protection on ranges 600 VDC or VAC
    
  
  
• Miscellaneous
  
  
  
  • Current consumption of meter is 1.3mA-1.8mA in most modes, NCV uses 7.6mA due to the led (7.3mA with backlight fully on).
    
  • Meter works down to 1.4V, where it turns off, battery symbol show at 7.3V.
    
  • The meter reading is stable down to about 1.8V, then it will show a random value.
    
  • Backlight is stable down to 5.2V then it start to fade and is just about off at 2.6V
    
  • The meter will usual show correct value in first display update
    
  • Viewing angle is good except from top
    
  • Display updates around 3 times/sec
    
  • Backlight display is directly controlled by a LDR and will turn slowly on when it gets darker (Backlight is disabled in NCV mode).
    
  • Will automatic turn power off in about 16 minutes
    
  • Standard probes cannot be pushed fully down.
    
  • Weight is 259g without accessories, but with batteries.
    
  • Size is 151 × 100 × 37mm.
    
  
  
• Probes
  
  
  
  • Probe resistance about 60mOhm for one.
    
  • Probe wire is on the thin side, not soft and 65cm long.
    
  
  

Oscilloscope Aarontek DSO338



This is a small oscilloscope with the most common functions.

Official specifications:

• Analog band width: 30MHz
  
• Maximum real time sampling rate: 200MS/s
  
• Vertical sensitivity: 50 mV/div ~ 200 V/div
  
• Horizontal time base range: 100mS/div ~ 125nS/div
  
• Maximum input voltage: 40 V (1X probe), 800 V (10X probe)
  
• Storage depth: 128KB
  
• Input resistance: 1M
  
• ADC precision: 8bits
  
• Coupling mode: AC/DC
  
• Trigger mode: Single, Normal, Automatic
  
• Trigger edge: Ascending/descending edge
  
• External trigger voltage 0 – 40 V
  
• Display: 2.4 inch – IPS – 320*240
  
• Power supply: 3000 mAh lithium battery
  
• Size: 90 × 70 × 28 mm
  
• Weight: 200g
  

• : Adjust timing, move curve, move trigger voltage, navigate menu.
  
• : Adjust voltage, move trigger position, select up/down trigger, navigate menu.
  
• AC/DC: Switch between AC and DC coupled.
  
• 1X/10X: Switch between 1X and 10X, this will affect voltage ranges.
  
• Menu: Show or hide the menu.
  
• RUN/STOP: Freeze/unfreeze the curve, also used with single trigger to trig the scope.
  
• Mode/Ok: Change mode for arrow keys (time-voltage/Curve location/Trig) and used for accepting settings in menu.
  
• Auto: Auto adjust voltage/time for a decent curve.
  
• Trig: Trigger mode: Auto, Single, Normal
  
• 50%: Move trigger to 50% amplitude on curve
  

• More measure: Enable/disable the measurement popup.
  
• Show cage: Usual called show grid and enables/disables the grid.
  
• Auto 50%: In auto trigger mode automatic move trigger to 50% amplitude on curve.
  
• Multi buffer: How many curves to average for the display.
  
• Save wave: Save or view captured waveforms, many keys change functions when in waveform view.
  
• Calibration: Zero the input without a probe connected.
  
• Night mode: Switch between white or black background.
  

• DC input impedance in 10x mode is 9.4Mohm with probe
  
• DC input impedance in 1x mode is 0.41Mohm with probe
  
• 3dB bandwidth is around 15MHz, with probe on 1X the input impedance is fairly low!
  
• Scope time ranges: 125ns, 250ns, 500ns, 1us, 2us, 5us, 10us, 20us, 50us, 100us, 200us, 500us, 1ms, 2ms, 5ms, 10ms, 20ms, 50ms, 100ms, 200ms, 500ms, 1.2s, 2s, 5s, 10s, 20s, 50s
  
• Time ranges above 1s use a scrolling display.
  
• The measurement popup is hidden at time settings of 100ms and slower.
  
• The measurement popup is hidden in normal or single trigger mode.
  
• In single and repeat trigger mode the trigger point is always at the left edge of the screen.
  
• At 500ns and faster the curve will always be an average of multiple traces in auto trigger mode
  
• Input capacitance with probe in 1x: 365pF and 382pF in lowest 3 ranges (Probe is 90pF in 1X mode).
  
• Input capacitance with probe in 10x: 25pF
  
• Scope 1x ranges: 50mV, 100mV, 200mV, 500mV, 1V, 2V, 5V, 10V
  
• Scope 10x ranges: 20V, 50V, 100V, 200V Why no overlap with the lower voltage, that would be useful
  
• AC coupling is true AC coupling with a capacitor.
  
• On the mini jack the center ring is not used, probe tip is tip of mini jack.
  
• When turned off the current draw is around 0.9uA
  
• When turned on the current draw is around 230mA
  
• The USB connection is charge only, there is no data connection.
  

Anyone has used or have an in-depth review of the Sonoff POW R2, like is it accurate in the power measurement?

(from a few reviews I read, it doesn't measure lower loads well, but how about higher loads?)

Multimeter design



This is a look on how a typical modern multimeter is designed, it is not a look at any specific meter, but more the general ways the different ranges on a multimeter is made. The article will include schematics and photos of circuit boards.
It is based on all the meter I have teared down during my reviews and datasheets for some multimeter chips.

Contents
    Protection
    Range switch
    Signal conditioning, ADC, reference, MCU and LCD driver
    Voltage (DC)
    Voltage AC
    The rectifier
    Low Z mode
    Current
    Ohm
    Continuity
    Diode
    Temperature
    Capacity
    Frequency
    Power supply
    Conclusion
    Notes

Lets start by a overview of the construction blocks in the meter.

• Input terminals, there will usual be 3 or 4 terminals
  
• Input protection, some protection is needed or the meter would not last long.
  
• Range selection, a switch to select what to measure. It will switch signals and report actual range to the MCU.
  
• Signal conditioning, adjust all the values the the ADC input range. This will be a mix of resistors and computer controlled switches, it may also contain a x10 amplifier.
  
• ADC, convert the analog value to a digital value.
  
• Reference, a reference voltage used for voltage and current ranges.
  
• MCU, the micro controller controls everything and format the digital value for the display.
  
• LCD driver, a LCD display requires some special voltages and scanning to work.
  
• LCD display, most multimeters uses a LCD display
  

DMM UNI-T UT195E



This is a industrial grade DMM designed for electricians. This is the simplest of the meters in the 195 series.



I got it without the box, but in the pouch.



With all parts inside.



That was the meter, the probes and a Chinese manual (I could download an English version).




Probes are branded UNI-T and rated for 20A, they have very low resistance and the 20A rating looks good enough.



With a tip cover they are CAT IV 600V or CAT III 1000V, without CAT II 1000V (This is fairly standard for probes).



The plugs are fully shrouded, but the shroud is a bit short



The meter is fairly heavy and the range switch easy to turn, this means it can easily be used with one hand, either lying flat or standing.



All the red plastic is slightly rubberized in feel including the range switch.
The red plastic works as bumbers from any direction.









The battery/fuse compartment is sealed and due to that the lid uses 5 screws, that usual stays in the lid (i.e. no lost screws).





The flashlight led and a hanger.



Display



All the segments are shown during power on.



Typical display during usage, it will show the number and selected measurement



Functions



Buttons:

• Range: Select manual range and change range, hold down to reactivate automatic ranging (Hz and C is always auto).
  
• Max/min: Capture maximum and minimum values, it will change between max/min, bargraph will show actual value. Hold down to disable.
  
• Rel: Shows values relative to current value, will also select manual range. Press again to disable.
  
• Hz %: Show frequency and duty cycle in AC voltage and current ranges, in Hz mode it will select duty cycle.
  
• Hold (Yellow): Will freeze the display reading, until pressed again.
  
• : Turn automatic backlight off until next power cycle.
  
• : Turn flashlight on or off.
  
• Select (Blue): Select DC/AC in voltage and current modes, continuity in ohm mode and can also be used to show duty cycle in Hz mode.
  

• LoZ: Low input impedance (300kOhm), range is always 600VAC.
  
• Off: Meter is turned off
  
• V: AC or DC voltage
  
• mV: AC or DC milli volt
  
• : Ohm and continuity.
  
• : Diode.
  
• : Capacitanse.
  
• Hz: Logical frequency input.
  
• uA: Micro ampere DC or AC
  
• mA: Milli ampere DC or AC
  
• A: Ampere DC or AC
  

• uAmA: Micro and milli ampere input.
  
• 20ADC: 20A DC current input.
  
• COM: The common terminal for all ranges.
  
• xxx: All other ranges.
  

• Volt and frequency
  
  
  
  • Volt ranges starts in AC
    
  • 1V AC readings is 5% down at 2kHz, rms will not work at that frequency
    
  • Frequency input do not require a zero crossing.
    
  • At 0.1Vrms frequency input range is from 1Hz to 4MHz
    
  • At 1Vrms frequency input range is from 1Hz to 24MHz
    
  • Duty cycle works from 7% to 97% at 100kHz with 4Vpp, precision is within 0.4.
    
  • Max/min needs about 390ms to capture a voltage, autorange is disabled when using this function.
    
  • Input impedance is 10-11Mohm on DC and AC
    
  • mVDC is high impedance up to about 2V where it drops to about 20kOhm, above 14V it will drop to 3kOhm
    
  • mVAC is the same, but capped by a 10MOhm resistor.
    
  • LowZ is constant 300kOhm input impedance and is locked in 600VAC range.
    
  • Input protection is 1000VDC/750VAC
    
  
  
• Current
  
  
  
  • 20A range has audible alarm above 20A
    
  • 20A range is fused with a 11A/1000V 10×38mm fuse
    
  • mAuA range is fused with a 0.6A/1000V 6×32mm fuse
    
  • Current ranges starts in DC
    
  • Peak can be selected in AAC.
    
  
  
• Ohm, continuity, diode and capacitance
  
  
  
  • Ohm needs about 2.6s to measure 100ohm
    
  • Ohm voltage is 1.0V open and 0.26mA shorted.
    
  • Continuity is very fast (About 10ms).
    
  • Continuity beeps when resistance is below 50ohm.
    
  • Continuity is 1.0V open and 0.26mA shorted
    
  • Diode range uses 3.8V, max. display is 3.000V at 0.33mA, max. current is 1.5mA shorted
    
  • 10uF takes about 1 seconds to measure.
    
  • 11000uF takes about 7 seconds to measure.
    
  • Overload protection is 1000V
    
  
  
• Miscellaneous
  
  
  
  • Current consumption of meter is 2.4 to 3mA (16mA with flashlight, 8mA with background light, max. 21mA).
    
  • Display starts fading around 3.2V and is gone at 2.2V, battery symbol show at 7.3V.
    
  • Readings will be correct until the display is faded.
    
  • Backlight fades with dropping voltage and is mostly gone at 5.5V
    
  • Flashlight fades with dropping voltage and is mostly gone at 3V
    
  • Viewing angle is good
    
  • Display updates around 3 times/sec
    
  • Bargraph updates around 10 times/sec
    
  • Backlight will automatic turn on when in dark surroundings
    
  • Flashlight will not turn off automatic, but turns off with the auto power off.
    
  • Will automatic turn power off in about 15 minutes.
    
  • Standard probes cannot be fully seated in the meter, but they do connect.
    
  • The meter usual need a few display update to before it display the value.
    
  • Weight is 490g without accessories, but with battery.
    
  • Size is 195 × 96 × 61mm
    
  
  
• Probes
  
  
  
  • Probe resistance 17mOhm for one, that is very low.
    
  • Probe wire are 88cm long and feels a bit stiff, probably due to the thickness.
    
  
  

Multimeter protection and safety



This is the second part of my multimeter design articles and it is about how a multimeter is protected for everyday use, where uses make mistakes and values are not what is expected.
For information about general multimeter design see: Multimeter design

Contents
    Voltage
    mV/Frequency/Temperature
    Ohm/Continuity/Diode/Capacity
    Current
    CAT ratings
    Conclusion

Voltage

What must the meter handle in voltage? The most obvious thing is higher voltage than selected range, this happens all the time on a auto range meter. Then there is AC when DC is selected and vice versa. Another obvious thing is that the input resistor must be able to handle the input voltage. When used in the real world, there is also something called transients, i.e. short, but very high voltage spikes.

Lets start with the input voltage, how high is it? A meter may be rated for 1000V DC/AC, do this mean the input voltage is up to 1000V? For power calculations basically yes, but not for maximum voltage, a sinus has 1.41 times higher voltage twice each cycle. That is the reason for 1000VDC / 600V/650/700VAC specifications (This means AC & DC has about the same peak voltage). The input resistor must be able to handle the 1000V or maybe 1500V, they are a bit hard to find and rather expensive.





Here is two high voltage resistor, the rest does it with multiple resistors.
But what about the chip, will it get 1000V or 1500V on its input pin when in the wrong range? The answer is very simple: Most chips include some protection on the input pins that can handle a few mA without damaging the chip. With a 10Mohm resistor 1500V input will at maximum give a current of 0.15mA, this can be easily handled by the chip and the resistor only needs to handle 0.1 Watt at 1000V, this is also easily done.

Basically a meter do not need any extra protection to handle 1000V DC/AC as long as the 10Mohm input resistor can handle it.
In the real world there is also transients, a meter rated CAT III 1000V must be able to handle 8000V for a short time, this is only 0.8mA with the above resistor and the multimeter chip will not have problems with it, but the chain of resistors may not be able to handle the voltage. There may also be an issue with the range switch and 8000V, sparks jumping around in the range switch is not a good idea.



To keep the input voltage limited meters uses this circuit, the resistor and PTC values may vary a little but is about 1kOhm (Some meters may use two PTC’s in series without the resistor and cheaper meters may leave out the 1kOhm resistor). The two MOV’s will keep the maximum voltage limited (Their voltage will also vary, depending on meter) and if the high voltage pulse is long the PTC will increase resistance to reduce current (Some meters use spark-gabs instead of MOV’s). This mean the internal design (10Mohm resistor and range switch) must be able to handle about 2000V, then the meter is safe. On some meters the 10Mohm input resistor is not protected by this circuit and with a good resistor it do not need to be.
For photos see the “ohm” section, the above is only half the input protection present in multimeters.


mV/Frequency/Temperature

For these measurement the meter may use the same input configuration as above, but most meters switch to another input configuration with lower input impedance, usual around 900kOhm, but some meters use other values. This works fine with low voltage, but what happens if the meter is connected to mains or higher with a 900kOhm input resistor?
At 1000V the 900kOhm means 1.1mA into the chip, this is not a issue, but what about the power in the resistor? 1000V 900kOhm is 1.1 Watt, not a hopeless amount of power, but the resistor needs some size to handle it and it also needs some size to handle 1000V.



Here are two examples on the 900kOhm resistor made to handle high voltage and some power, but it is not present in that many meters. If the manufacturer want to make a good meter they often use another solution.



That is not a normal transistor coupling, the transistors are used as zener diodes.



Here is the voltage/current curve for one transistor (BC547), it works as a Zener diode at around 9.6V. The zener voltage will not be very precise and depend on the transistor used, the ones used in multimeters usual has a much lower zener voltage (The clamping is around 2.5V to 3V).



A voltage sweep on a pair show that it will drain current when voltage gets too high in either direction.



Expanded the current scale shows that there is very little leak current and much better than regular zener diodes.

Back to the circuit again. This pair means that the 900kOhm resistor will see less than 10V, this can also be used with much smaller resistor values without any problems. But what about the transistors, with 1000V input the current will be about 0.5A until the PTC warms up, many transistors can handle 0.5A for a short time. When the PTC warms the current will be much less (Steady state maximum will be below 30mA with a 1W PTC). A 8000V spike is a bit more nasty, there the peak current will be 4A.



They are usual very easy to spot on the circuit board and there may be more than one pair.



The above was about the good way to secure the voltage input, the cheap multimeters do not do it that way. It is something like the above, the PTC and clamp is still connected, but the 900kOhm resistor may not be protected by it. I believe this configuration is to make the range switch as simple as possible, because it matches Ohm/Continuity/Diode/Capacity.



A photo of the 900kOhm or 910kOhm in this case (R25: marked 914), it is not exactly a setup that can handle high voltage or any power (The ruler is with mm ticks). It may survive 250VAC for a short while, but will not handle higher voltages or transients very well. This size resistor is typically rated for 150V! This input configuration is used in many cheap meters.



Ohm/Continuity/Diode/Capacity

In these ranges there is another problem, the meter must supply some current on the measurement terminal and this current must be high enough for reliable measure low ohmic resistors or to test LED’s, this usual means nearly a mA. At the same time it must be able to withstand that the probes is connected to some voltage, preferable mains or higher. A good meter can handle more than 1000V input in ohms range.



For this protection two PTC’s are needed, one for supplying the current and another for measuring the voltage, this way any loss in the PTC will not affect precision (as long as the circuit can supply enough voltage).



Looking at input protection there is always MOV’s on both paths, why is that? This is probably to avoid having 8000V transients inside the range switch, with the MOV’s it is limited to below 2000V. These MOV’s do not add any protection when the range is selected, there voltage is limited by the transistor pairs.







Here are some examples, one meter has replaced the 1kOhm resistors with PTC’s on two meters there is a LowZ mode with one and two PTC’s. There is also a meter where the MOV’s has been replaces by spark gabs. Note: PTC’s are usual the ones with heat shrink.



On cheap meters it is made different and much less safe. The PTC is only used on the current output and without a 1kOhm series resistor and the 900kOhm is the same as in mV/Frequency/Temperature, see above about that. The PTC is usual somewhere from 0.5kOhm to 1.5kOhm.



And some examples where the PTC and the transistor pair is mounted next to each other.

The above covers the best way to do protection and the bad way to do protection, there is a lot of meters that is somewhere in-between.




Current

The current inputs must be protected from smaller overloads that will damage the shunt resistors, but also for user mistakes like connecting the current range directly across mains voltage.

In current modes a fuse can be used to protect the meter, but there are some limitations.
The first one is the uA range with a 100ohm resistor, it shares fuse with the mA range. With a 0.2A fuse it means 4 watt in the resistor and what about a 0.6A range? In praxis it will be considerable more because the fuse do not blow exactly at rated current and not very fast either.



The solution is often to use a diode bridge with an extra diode in the middle to short it. This can be build with a bridge and one extra diode or with 5 diodes. This means 3 diodes is present with either polarity and will limit the voltage to a safe value for the uA shunt. This bridge usual covers both the mA and uA shunt, but not always.
In a careful meter design the diodes overload characteristic must be matches to the resistors and fuse characteristic to secure that the fuse will blow before the diodes or resistors with any overload current maybe up to 1000A.



Here is a voltage sweep of a 5 diode protection bridge made with (cheap) 1N4007 diodes, it will protect the shunt from more than a few volts.



But these diode are not prefect for very low current measurement, there is a small leakage current, depending on voltage (A 6000 count meter will usual have 0.6V across the shunt when at maximum). This current is very temperature depend, i.e. the meter may loose a bit of precision in uA on a very hot day.



There is nothing saying it has to be exactly 5 diodes, it could be 6 diodes, but 4 needs a meter with very low burden voltage (Maybe a 2000 count meter). There are some meters that uses two antiparallel diodes, again they must have very low burden voltage.





Here are some examples on the bridge coupled shunt protection, one of them with a larger diode in the centre (It must handle double of the other diodes) and one with a real diode bridge package.



An alternate way is to use a TVS diode, this is often seen in the cheaper meters. This may work for short transients, but may not protect the uA current shunt resistor and TVS from overheating with longer time overloads.



And some examples on TVS diodes.



Many different sizes of fuses are used in multimeters, but not all are suitable for the job. They can all protect against a small over current when working at low voltage, but handle the user mistake of having the probe in the current plugs while trying to measure a high voltage requires much more of the fuse. The fuses are always fast types.
To handle high voltage with high current the fuse must be rated to break the same voltage as the meter is rated for and it must be able to break very high currents, this means a large ceramic HRC fuse (HRC stands for High Rupture Capacity). The is mostly interesting when working with power distribution or in industrial settings, power after a normal mains outlet is not that dangerous.




These fuses are too small (10mm & 20mm long) and will not protect the meter and user against high energy shorts, but will be fine on a bench with low voltage and also on mains as long as it has a not too large fuse.



This is the high quality multimeter fuses (38mm long) that can break just about any current up to 1000V, but they are usual rather expensive and is never used in cheap meters.




Sometimes meters uses a PTC instead of a fuse for mA, this again is mostly for bench and low volt use. The nice feature is that is recovers automatic after an overload, the bad feature is that is often has higher resistance than a regular fuse, i.e. the meter will have higher burden voltage.

When a fuse is blown the current input must be able to handle high voltage, CAT ratings says twice the rated voltage. This means some distance from fuses and current terminals to other stuff in the meter, maybe slots in the circuit board and plastic shields.
One detail is meters with sensing for a plug on the current inputs, it can be made optical, mechanical or electric with slot terminals.



A optical sense.



A mechanical sense.



Two electric sense systems, one with 5Mohm resistors to block any voltage/current from the rest of the multimeter. In the first sense system the meter will probably fry if the fuse blows while measuring high voltage.



CAT ratings

I have referred to CAT ratings a few times, they are standards for how large and powerful transients can be expected on mains volt in different locations. Locations are divided in for different groups (Some standards do not include CAT I), they are roughly:

• CAT I: Electronic and other equipment after the mains transformer.
  
• CAT II: Anything connected to normal household outlets.
  
• CAT III: Industrial and other high current installations.
  
• CAT IV: Distribution and outdoor conductors.
  

DMM Aneng H01



This is a fairly cheap Aneng multimeter, but is has most of the common ranges.



I got the meter without a box



It included the meter, probes and a instruction sheet that do not match the meter.





Probes are not branded and are specified for CAT III, this cannot be true with that much tip exposed.



The plug is fully shrouded but very short with 13.7mm shroud.



Pressing on the meter the rotary switch can be turned when the meter is on its tilt stand.






















Display



The above picture shows all the segments on the display, a few of them are not used.



Usually the meter shows the selected range and the value.



The Non contact voltage detector is the usual bars.



Functions



Buttons:

• SEL (red): Select AC/DC in voltage and current and changes between diode/continuity.
  
• RAN (yellow): Switch to manual range and select range, hold down to activate automatic ranging again.
  
• Hold (red): Freezes the current displayed value.
  

• Off: Meter is turned off.
  
• V: Voltage DC and AC, use SEL to switch. The VDC range has a mV range
  
• : Resistance
  
• : Diode and continuity
  
• : Capacitance
  
• Hz: Frequency.
  
• NCV: Non contact voltage detection.
  
• uA: The uA range.
  
• mA: The mA range.
  
• A: The A range.
  
• Off: Meter is turned off.
  

• A: High current, maximum current is 10A
  
• CON: The common terminal for all ranges.
  
• xxx: All other ranges.
  

• Volt and frequency
  
  
  
  • At 0.1Vrms logical frequency input (Hz) range is from 0.8Hz to 3MHz
    
  • At 1Vrms logical frequency input (Hz) range is from 0.5Hz to 30MHz
    
  • Logical frequency input (Hz) requires a zero crossing.
    
  • 1 VAC is 5% down at 2.4kHz (RMS will not work at the frequency).
    
  • There is audible alarm above 600V
    
  • Input impedance is 10-11Mohm on mVDC/mVAC/DC/AC
    
  • Frequency input has high input impedance up to about 2V then drops to about 1-3kOhm
    
  • Rated overload protection on V ranges is 600VDC/AC
    
  
  
• Current
  
  
  
  • Overload protection in uA and mA is a SMD fuse rated for 0.25A according to the circuit board text.
    
  • There is no overload protection in ampere, the range is unfused.
    
  • There is audible alarm on the 10A range when at 10A or above.
    
  • The mA fuse cannot handle the full 0.4A for long, because it is only 0.25A
    
  
  
• Ohm, continuity, diode and capacitance
  
  
  
  • Ohm needs about 2.8s to measure 100ohm
    
  • Ohm is 1.0V open and 0.35mA shorted
    
  • Continuity is fast (20ms).
    
  • Continuity beeps when resistance is below 50ohm
    
  • Continuity is 2.1V open and 0.34mA shorted
    
  • Diode range uses 2.3V, max. display is 2.000V at 0.14mA, max. current is 1.2mA shorted
    
  • 10uF takes about 2.2 seconds to measure.
    
  • Rated overload protection on ohm ranges is 250 VDC or VAC
    
  
  
• Miscellaneous
  
  
  
  • Meter in off has down to 1kOhm input impedance, i.e. a PTC
    
  • Current consumption of meter is 1.0mA-1.8mA, VDC has the highest current drain.
    
  • Meter works down to 2.2V, where it may turn off or reset, battery symbol show at 2.3V.
    
  • The meter reading is stable until the meter turns off.
    
  • The meter usual shows correct in first display update, but may delay that update a second.
    
  • Viewing angle is good, except from the top.
    
  • Display updates around 3 times/sec
    
  • Will automatic turn power off in about 16 minutes
    
  • Standard probes cannot be pushed fully down.
    
  • Weight is 170g with batteries and sleeve.
    
  • Size is 146 × 72 × 33mm.
    
  
  
• Probes
  
  
  
  • Probe resistance about 110mOhm for one.
    
  • Probe wire 84cm long.
    
  
  

I received the Nitecore NTP40 from Nitecore for the review.
The NTP40 is a mechanical pencil made out of titanium alloy.

It comes in this box

Usually, tactical pens are made with a rather bulky and over-sturdy design, resulting in an object that looks great, but is almost impossible to use in the real world regularly.
That can be due to super aggressive knurling, high weight, and body with a squared profile.
The NTP40 is not a tactical pencil in that regard. It is very elegant in design and perfectly machined out of titanium alloy, while maintaining a regular mechanical pencil form factor.

The body is sleek except for some non-aggressive circular knurling near the tip, providing a comfortable grip while in use. I like how the body is finely brushed, plus it contrasts with the screws that keep the clip in place and with the cap that has a crystallized finish (to me it looks somehow stone-tumbled finished).

The NTP40 is not only good looking from the outside, the insides contribute to the functionality of the pencil. The mechanism is a German Schmidth Feinminen System, with a graphite diameter of 0.5 mm, widely available.

When assembled, the lead holder is kept in place with a threaded bezel that screws on the titanium body itself, resulting in a very firm and stable tip. It feels like it’s really part of the pencil.

Here are a few pics of all the part that the NTP40 is made of. All the threads are well made and work smoothly.

I definitely plan to keep and use the NTP40 as part of my writing equipment, loaded with the super soft 4B leads that I love in mechanical pencils.

Here with other writing instruments

Thanks to: AntoLed, Won, Zampa.

heh, me and budda simultaniously released review of Nitecore NTP40, so you guys have all the information now.

OFFICIAL PAGE OF NTP40

Package and appearance
 

The pencil is packed in the exact same rough black box as the previous model.

 The only difference is in the pattern of silver embossing, somewhat different for each of these two models. In general, although the packaging is clearly good and not cheap, I would not refer it to the luxary one. In any case, it is definetely presentable.

Inside – everything is the same as NTP30. The same orange piece of paper-tip, which describes the main advantages of this model.

Well, here is the pencil itself, defentely decent appearance. At that time there is no tactical component here. Although, if desired, of course, and it can be very painful to stick NTP40 in the side of your opponent.

 I think that it will be right to show both models side by side, Nitecore NTP30 and Nitecore NTP40. In general, there is only one obvious common feature here – this is a clip.

Actually, the latter sits on a pair of torxes and, if desired, it can be removed. Although neither practical nor aesthetic sense, I do not see this. The chamfers of the clip are neatly removed, it will not scratch neither clothes nor fingers.

And if the rest of the pencil is evenly gray, then there are some “tiles” of the pattern on the button. I think that this is some kind of conscious design element, since it is clearly not a defect in grinding or processing.
 

The opposite part of the handle is covered with a wavy knurling. Actually, grip is comfortable. It is not heavy or uncomfortable, in fact everything is done as it should.

It is clear that when you press the button, the stylus rod moves out.

It would seem a pencil and nothing more, what can be so complicated here? But no, analysis shows that there are a lot of different elements.

By the way, i never before saw such a slate. In fact, this Schmidt Fineminen system. A replaceable module with 4 slatescosts as much as 12 bucks at ebay. On the other hand, absolutely no one bothers you to buy the most common 0.5 slate pencils and insert them inside this module, since it’s completely open from the end, as can be seen in the photo below.

in fact, the lower edge of the button is inserted in the same hole

A tip is screwed on the opposite edge, which is inserted into another external element. So there will be no backlash of the lead. The mechanism becomes monolithic homogeneous.

By the way, apparently, this particular nozzle allows you to turn an ordinary ballpoint pen into a mechanical pencil.

Well, actually, as a pencil writes? I am not a draftsman, and I draw at a level that allows you to understand that this is a wolf, not a trilobite. So here my impression will be exclusively amateur. The stylus is quite soft on the paper, it is definitely convenient to draw. I think that with such a price tag and such a writing module, there should be no questions about ergonomics and the quality of the lead.

Overal impressions

It is clear that this is a very, very niche product. Even more niche than NTK10. Painters, as I understand it, need to change different types of slate in the process of drawing, and here it will be inconvenient. Draftsmen, with the development of all kinds of autocad and similar softwarwe, are likely to have become extinct as a class.

Nevertheless, I am sure that there is a small category of people (the same draftsmen) who, due to nostalgia for pencil times, will be very pleased with such a gift. Maybe there is still some other categories of people, who knows.

After all, the appearance and presentness is at a height here. And the functionality itself is completely wealthy, it is definitely convenient to draw with a pencil. The price tag is far, far from small, but not at all outlined in the background of all Montblanc, Montegrappa and Caran D`ache. But what to say, even Faber Castell has gift models. And if there is – then there is demand. And judging by what I saw in the Nitecore NTP40, this mechanical pencil is not worse than the above competitors. The only difference is in design, here it is expected to be more tactical and Nitecore style)

DMM Kyoritsu KEW1062



Kyoritsu is a Japanese test equipment manufacturer, this multimeter is one of their top models.





I got it in a cardboard box designed for this model. It only list the meter model, no further information, except the drawing of the meters front.



The box contained the meter, batteries, test probes and a manual in Japanese and English. No thermocoupler or pouch.
The manual is very thorough with functions and specifications.





The probes has removable tip covers in soft silicone, the tip and tip cover has the usual CAT markings.



The shrouded plug is a bit on the short size.



The range switch is fairly easy to turn and with this heavy meter it is stable both lying and standing. The shutters in the ampere range the movement of the range switch can be blocked by inserted plugs.









The battery lid lists battery type and fuse ratings, but not size of fuses. There is a good marking for what fuse goes where.



Display



The above picture shows all the segments on the display. The contrast it not very good. The backlight will help in dark surroundings, but not with shadows from a bright lamp.



Typical display during usage, it will show the number, bargraph and what measurement is selected.



When frequency is selected in AC ranges the voltage moves to the secondary display



In DC volt a combined AC and DC mode can be selected.

Secondary display functions (After / is small display):

• AC Volt and mV: VAC, frequency/VAC, frequency/duty cycle, dBV/VAC, dBm/impedance
  
• DC Volt: VDC, DC+AC, VDC/VAC
  
• Current: ADC, AAC, AC+DC, DC/AC, frequency/duty cycle
  
• REL: V/ref, percent/ref, A/ref, percent/ref, ohm/ref, percent/ref, capacity/ref, percent/ref
  
• Capacity: value/range
  
• min/max: value/Time
  
• Memory: Memory number or depending on configuration time.
  

• Shift (Yellow): Select the yellow functions on the buttons.
  
• Range: Press to select manual ranging, press again to change range, hold down for automatic ranging. In dbM it will select impedance.
  
• Hold: Freeze display, press twice to activate auto-hold and 3 times to select peak detect mode.
  
• Light: Press to turn backlight on, hold down to turn backlight off.
  
• Select (Blue): Select blue modes on rotary dial.
  
• REL/%: Remember current value and show new values relative to this, either as a value or as percent.
  
• Min/max: Select between max/min/avg, max, min, avg. The max/min/avg shows current value. Hold down to disable.
  
• Memory: Activate memory functions, see below.
  

• RMS: Select RMS mode for AC measurement
  
• Filter: Enable a low pass filter for AC measurement.
  
• Setup: Configuration of meter, this is clock, default dBm impedance, default RMS/mean, default logging interval, sound on/off.
  
• Mean: Use mean for AC measurements.
  

• Memory: Hold down to leave memory mode.
  
• Save: Select single point save. Next pressed on save will each save a single measurement (Space for 100). Hold down the key to delete data.
  
• Read: Read saved data, press Save or Log to select memory to view, use arrows to move in data.
  
• Log: Select logging interval with arrows, then start logging on the second press (Only one session can be recorded with up to 10000 records). Hold down the key to delete data.
  
• : Used for adjusting logging interval and selecting memory no.
  

• Off: Meter is turned off
  
• VAC: Show AC voltage and frequency, use the blue button to select frequency, dBm or dBV.
  
• mVAC: Show AC millivoltage and frequency, use SELECT for frequency, dBm or dBV.
  
• VDC: Show DC voltage, use SELECT for AC+DC or AC,DC
  
• mVDC: Show DC millivoltage.
  
• : Continuity and diode.
  
• : Resistance, use SELECT for low power resistance.
  
• : capacitance.
  
• Temp: Temperature
  
• uA: Micro ampere current DC, AC, AC+DC, AC,DC and frequency can be selected with SELECT.
  
• mA: Milli ampere current DC, AC, AC+DC, AC,DC and frequency can be selected with SELECT.
  
• A: Ampere current DC, AC, AC+DC, AC,DC and frequency can be selected with SELECT.
  
• Off: Meter is turned off
  

• 10A: High current.
  
• mAuA: The lower current ranges, the selector switch will change between two different shunts.
  
• CON: The common terminal for all ranges.
  
• xxx: All other ranges.
  

• Volt and frequency
  
  
  
  • At 10mVrms mVAC frequency input range is from 1.4Hz to 60kHz
    
  • At 100mVrms mVAC frequency input range can be stretched to 75kHz.
    
  • At 1Vrms VAC frequency input range works from 1.4Hz to 70kHz
    
  • At 2Vrms VAC frequency input range works from 1.4Hz to 150kHz
    
  • Frequency input do not requires a zero crossing.
    
  • Duty cycle in mVAC works from 13% to 8% at 1kHz with 1Vpp, precision is within 1.0.
    
  • Max/min needs about 110ms to capture a voltage on DC.
    
  • Peak needs about 0.15ms to capture a positive DC voltage.
    
  • 1 VAC is 5% down at 220kHz, AC+DC is similar(RMS will not work at the frequency).
    
  • 1 VAC is 5% down at 100Hz when filter is activated (RMS will not work at the frequency).
    
  • dBm reference impedance can be select from: 4, 8, 16, 32, 50, 75, 91, 110, 125, 135, 150, 200, 250, 300, 400, 600, 800, 900, 1000, 1200. Default is 600.
    
  • Input impedance is 10..11Mohm on DC, AC and mVAC. AC and mVAC is capacitive coupled.
    
  • mV DC range about 110Mohm up to around 4V, then it will drop to about 1Mohm at 8V and continue to drop slowly
    
  • Over voltage protection is 1000VAC/DC
    
  
  
• Current
  
  
  
  • A range has audible alarm above 10.5A
    
  • uA & mA current is protected by a 0.44A/1000V 10.3×35mm (38mm fits) fuse, this means any current above 400mA can blow the fuse.
    
  • 10A current is protected by a 10A/1000V 10.3×38mm fuse.
    
  
  
• Ohm, Continuity, diode and capacitance
  
  
  
  • Ohm needs about 3.4s to measure 100ohm, low resolution mode do not improve speed.
    
  • Low power ohm needs about 2.2s to measure 100ohm (It uses a higher range).
    
  • Ohm is 2.2V open and 0.81mA shorted
    
  • Low power ohm is 0.56V open and 0.005mA shorted
    
  • Continuity is very fast (Below 10ms, but not latched).
    
  • Continuity beeps when resistance is below 100ohm.
    
  • Continuity is 3.5V open and 0.44mA shorted
    
  • Diode range uses 3.5V, max. display is 2.4V at 0.19mA, max. current is 0.43mA shorted
    
  • 10uF takes about 5.3 seconds to measure.
    
  • 11000uF takes about 12 seconds to measure.
    
  • Over voltage protection is 1000VAC/DC
    
  
  
• Miscellaneous
  
  
  
  • Current consumption of meter is 41mA in AC and 16mA in DC, other ranges is around 16mA (With backlight in AC total is 46mA).
    
  • Meter works down to 2.0V where it turns display off, battery symbol shows at 4.2V.
    
  • Reading do not change with battery voltage.
    
  • Backlight is stable until about 2.2V.
    
  • When meter is turned off it uses about 0.3mA from the batteries.
    
  • It is possible to switch between RMS and mean in AC readings, default is RMS, but can be changed in configuration.
    
  • Meter can be started in averaging mode, where it will average 8 readings (Hold down min/max while powering on).
    
  • Logging interval: 1s, 2s, 5s, 10s, 30s, 1m, 10m, 30m
    
  • The meter will often show the correct value in first display update, but do also sometimes slowly change to a value.
    
  • Viewing angle is good, but contrast is fairly low.
    
  • Display updates around 6 times/sec
    
  • Bargraph updates 15 times/sec.
    
  • Backlight will automatic turn off in about 60 seconds.
    
  • Meter will automatic turn off in 20 minutes, this can be disabled.
    
  • Standard probes cannot be seated completely.
    
  • Weight is 572g without accessories, but with batteries.
    
  • Size is 192 × 90 × 48mm.
    
  
  
• Probes
  
  
  
  • Probe resistance 29mOhm for one.
    
  • Probe wire is fairly soft and 89cm long.
    
  
  

DMM UNI-T UT125C



Uni-T has a large selection of DMM in their program, this model is a compact meter with build in probes and a broad selection of ranges.



The meter arrived in a red box with Chinese writing.



The box contained the meter and a instruction sheet in English.




The probes are rated for 600V and CAT II or CATII depending on if tip cover is used.



The meter is fairly light weight and you have to press on it or use two hands to rotate the switch.











Display




The above picture shows all the segments on the display.



Typical display during usage, it will show the number and what measurement is selected.



The electric field detection (NCV) is a red led at the top of the display, if the meter is on it will light up when a field is detected, there is no sound or display indication. This detector is very sensitive and the indicator turned on very frequently.



Functions



Buttons: