Transistor Curve Tracer

I’ve always wanted a transistor curve tracer. It’s the best way of understanding what a device does.Having built and used this one, I finally understand the difference between the various flavours of FET.

It’s useful for

matching transistors
measuring the gain of bipolar transistors
measuring the threshold of MOSFETs
measuring the cutoff of JFETs
measuring the forward voltage of diodes
measuring the breakdown voltage of Zeners
and so on.
I was very impressed when I bought one of the wonderful LCR-T4 testers by Markus Frejek and others but I wanted it to tell me more about the components so I started to design my own tester.

I began by using the same screen as the LCR-T4 but it doesn’t have a high enough resolution so I changed to a 320x240 2.8” LCD. It happens to be a colour touch-screen which is nice. The curve tracer runs on an Arduino Pro Mini 5V Atmega328p 16MHz and is powered by 4 AA cells.”