MTester LCR-T4 12864 LCD

One day I got a cheap MTester from some Chinese source. MTester is a cheap electronics component measurement device. It can detect component types and measure them. The meter has automatic detection PNP and NPN type bipolar transistors , N, P -channel MOSFET, JFET FET , diodes , two diodes, thyristors , resistors , capacitors , inductors.


The meter features single key measurement operation: Just press key and meter does measurement automatically (determine component type and measure it’s values). Each test takes typically about two seconds. It is working very well taking into account that it costs less than 10 Euros/USD on sale in circuit board format (there are more expensive cased versions). In my pictures I have installed the circuit board on the top if a small plastic box that has the 9V battery inside it.


On the capacitors measurements this tester measured besides capacitance also ESR (series resistance) and Capacitor voltage loss (Vloss). Both ESR and Vloss can give you information on the quality of capacitor. The voltage loss (Vloss) is a voltage measurement taken shortly after a load pulse has charged the capacitor. The reached load voltage is lost with electrolytic capacitors after a short period of time can be caused by by a parallel connected resistor and/or internal load dispersion inside capacitor.

Capacitors with more than few percentage voltage loss are suspect to be bad. Significant voltage loss % does mean the old capacitor is drying out. Please note that paper and electrolytic (particularly the higher voltage types) will [almost] always show some Vloss though, regardless of their state.

What is the hardware that does those test wonders? The display uses 12864 lcd LCD (128 * 64 characters) and the microcontroller is Atmega328 (same as in Arduino Uno). The device can be powered with 6FF22 9V Battery,

Here are some videos on this tester:

EEVblog #1020 – Is A $7 LCR / Component Tester Any Good?

LCR meter – MTester T7 – Transistor tester review

Component tester review/demo (MTester)

Links to more information:

MTester no version on LCD – how to check the version?

Transistor Tester (MTester) talks about reflashing this type of tester with a new MTester firmware.

If you get a circuit board, bit want a case for it, check out Search Engine for 3D printable Models for “mtester” – at the time of writing it found 15 printable 3D Models.


  1. Tomi Engdahl says:

    Amazing device you must have one , helpful gadgets

    The unit is very handy however it has problems with certain type of Triacs.

    I bought one of these from eBay ages ago when they were really cheap. It’s so useful for quick checks when assembling circuits. I love mine

    It is a cheap tester and good for quick tests but I also use a curve tracer and other more expensive test equipment . I do not trust it completely The Unit is OK for a quick test, diodes, caps resistors as well as inductors. However, the Tester I have will show a PNP such as a bdx 34x c as a NPN. It often makes the mistake of identifying the correct polarity of a darlington. I do not trust it at all in that respect. Regular bipolar, Mosfet check ok. 4401, 2n2222 and other small signal all check properly except mpsa13 npn darlington small signal T092 checks as a PNP one time and an NPN another time! . Have used it hundreds of times and it the only other flaw is that the bottom of the display where the #3 probe on the video is .. that is washed out. A good value for a cheap tester.

  2. Tomi Engdahl says:

    Inductance measurements results with Multi component testers

    Small common mode choke (ferrite core):
    1.39 mH result
    Turn around get first 1.20 mH, then next measurement same direction 1.39 mH
    Turn around again gets 1.20 mH and then 1.38 mH

    Mains transformer low voltage coil 246 mH
    Turn around 158 mH and next measurement same direction 234 mH
    Tunr aroun 169 mH and next 245 mH

    Another signal transformer 0.53 mH
    Other way 0.52 mH next 0.53 mH

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  4. Tomi Engdahl says:

    Amazing device you must have one , helpful gadgets

  5. Tomi Engdahl says:

    Quite similar looking in different form factor:


  6. Tomi Engdahl says:

    Arduino Electronic Component Tester
    Please check out the link for more information:


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