Test Thyristor and Triac using this circuit. Pay attention on mains voltage!
Thyristor – Triac Tester - [Link]
coremelt.net writes:
With this tool you can test various electronic components like diodes, LEDs, all kinds of transistors (PNP, NPN, several types of MOSFETs), capacitors, resistors as well as triacs and thyristors. It will show you several physical characteristics after the test was completed, like forward voltages, (gate) capacity and amplification factor. More over, it will show the polarity of the component and identifies the several pins of a package. A very nice and sophisticated project I host for Markus Frejek. I’ve done an additional layout for the device you can see on the left side. This project has found a lot of fans, including myself. The device is powered by an AVR ATmega 8 MCU.
Component tester - [Link]

dangerousprototypes.com writes:
After our recent post about the commercial semi-conductor tester we started a discussion about building a similar open source project. What came up is this AVR based transistor tester (machine translation) by Markus.
It’s built around an ATmega8 IC that interfaces with a standard HD44780 16×2 character LCD. The circuit that does the testing is simplicity itself. Three pairs of resistors are connected to 6 pins of the microcontroller, and each pair is connected on the other end to one of the transistor pins.
The theory of operation is also relatively simple. The microcontroller cycles through different patterns on its output pins until a recognizable pattern is read on its input pins. It supports a very large range of devices:
- NPN and PNP bipolar junction transistors.
- P and N channel, enhanced and D type mosfet transistors.
- P and N channel JFET transistors.
- Thyristor.
- Triac.
- Common anode and common cathode dual diodes.
- Two diodes in connected in anti-parallel or series configuration.
- Single diode.
- Resistor.
- Capacitor.
Arup and Fcobcn have already built one for themselves. Join the discussion and add your input to our development of an open source part tester.
AVR-based transitor tester - [Link]













