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:
Via the forum.