I saw an interesting kit at banggood.com and decided to try it: DIY Meter Tester Kit For Capacitance ESR Inductance Resistor NPN PNP Mosfet M168 . The reasons for interests are good specifications, based on open source hardware design and price is reasonable ($12.22 / 9.37 Euro).
DIY Meter Tester Kit For Capacitance ESR Inductance Resistor NPN PNP Mosfet M168 is an 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. You can connect the measurement wires to components as you want, the automatic detection pin definitions will tell which wire is which pin.
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 time is about two seconds , only large capacitance and inductance measurements will take a long time. The device has auto power off with delay.
The device can be powered with 6FF22 9V Battery, or DC 5.5V ~ 12V via DC socket. The kit has 25 mA operating current and 20 nA current in shutdown, so suitable for battery operation (without separate power switch).
Resistor: 0.5Ω ~ 50MΩ (resolution is 0.1Ohm)
Capacitor: 30pF ~ 100mF (resolution up to 1PF)
Inductance: 0.01MH ~ 10H
Potentiometer: Support two measuring resistors connect at the same time -> can measure potentiometer
ESR measurement: Can detect more than 2UF capacitor equivalent series resistance (ESR), with a resolution of 0.01Ohm.
Bipolar transistor: amplification factor (B) and conduction voltage emitter junction (Uf).
MOSFET: threshold voltage and gate capacitance measurement
Thyristor and TRIAC: meter shows only the component pin-out
Diode: diode direction, voltage drop and capacitance
Zener-diode: If reverse break down Voltage is below 4.5V, these are shown as two diodes with different voltage drops
This device is sold as DIY kit that you must solder yourself. The kit comes in a small plastic bag that included all the components and circuit board.
The parts and board are excellent quality, no missing or wrong parts.
Beginners beware – there are no instructions or documentation with this “kit”, it is a PC board and a bag of parts. That’s it. But, that’s okay because when you install the parts per the component outline/value printed on the top of the PC board.
When you put all components in right places add the solder – you’ll end up with a working instrument.
Only problem I had building: There was no clear indication the way the button should installed to circuit board. I first accidentally installed in wring way, and the circuit worked a little bit strangely (but almost worked). When I turned around it (needed de-soldering and re-soldering), everything stated works well as designed.
Here is my circuit (with my own measurement leads added to kit) measuring BS170 FET:
This kit is an accurate implementation of the open source project described in all detail at http://www.mikrocontroller.net/attachment/143813/TTester_096k.pdf and a newer version of it at http://www.mikrocontroller.net/attachment/164956/ttester_eng104k.pdf. Since the PC board in this kit implements the open source project schematic with 100% accuracy, the board also uses the open source AVR code. This allows you to extend the design, change its behavior or just use it as is, the choice is yours.
This version uses the ATMEGA328P-PU (same 28 pin DIP package that the Arduino UNO uses). The unit does provide the same 2.1/5.5 MM power jack as used on Arduino’s if you want to power it with a 9vdc wallwart.
There are few negative things on the design:
1) The press to test switch is lacking a large surface to press.You might want to add a small cap to it or replace the original button with your own more user friendly button.
2) The choice of LCD (white on blue) requires the use of the LED backlight always. This backlight uses considerable battery power. The display is standard 1602 device so it should be possible to change if you want to experiment (cost few dollars).
3) The placement of the 3 point terminal strip in front of the SMD pad areas is not good: Having the terminal in front of the pads makes it almost impossible to easily test surface mount parts by pressing them on the board. If you always use measurement wires this is not a problem.
4) The ATMEGA328P processor: while it was in a good static shielding bag, there was no lead protection, it was just tossed in with the other parts which resulting in some bent pins.
5) ESR measurement and the results of inductance measurement are not very accurate.
There are some negative things, but overall I was very satisfied with DIY Meter Tester Kit For Capacitance ESR Inductance Resistor NPN PNP Mosfet M168 kit. This useful instrument will sit on my electronics lab for a long time.