DIY Tr Tester Duoyi DY294 repaired
This page shows how I could fix broken DY294 by reverse polarity power supply. It works for over-voltage damage, too.
Transistor
DIY 
DIY DIY Tr/FET Tester completed
According to the cirduit design finished in below link, I have just finished assembly of Transistor/FET tester (hFE measurement device). It can fix the Emitter current (Source curr…（Read more）
DIY DIY Tr/FET Tester, ultimate hFE/Vgs/IDSS measurement device
I built ultimate hFE tester. I gathered many good ideas from internet and made up the best version I could imagine. It enables measurement of hFE under constant emitter current. This achieves also Vgs and IDSS of FET measurement.