14-11-2016, 06:37 PM
That circuit in post#1 looks very like the transistor I made when I was an older teenager in the late 1970s.
It is the right tool for the job. Mine runs on an HT of 10 volts and measures the HFE at a fixed collector current set by a selector and fixed collector resistors and an opamp that flashes a couple of LEDs to aid setting VCE.
All transistors are tested at 5 volts for VCE.
The original collector current is 2ma to 100ma but recently without modification I have run it up to 2 amps with a bench PSU without issue.
It did a champion job of sorting out all those unmarked transistors that were sold in big bags all those years ago.
It still lives and works to this day.
It is the right tool for the job. Mine runs on an HT of 10 volts and measures the HFE at a fixed collector current set by a selector and fixed collector resistors and an opamp that flashes a couple of LEDs to aid setting VCE.
All transistors are tested at 5 volts for VCE.
The original collector current is 2ma to 100ma but recently without modification I have run it up to 2 amps with a bench PSU without issue.
It did a champion job of sorting out all those unmarked transistors that were sold in big bags all those years ago.
It still lives and works to this day.
