Measure silicon transistor Hfe

[stefcuypers]

Hellow everyone,

I have a nice (old) Fluke DMM without transistor measuring options. Is it possible to measure the hfe of silicon transistor wit an other option? Like RG keen's way to measure Germaniums by measuring the DC voltage? Thanks a lot and have a nice week.

[John Lyons]

You can just build the GEO tester and that will work for Silicon devices.
You don't need to do the math to get the gain and leakage though.
Just pop em in and that's your Hfe.

john

[stefcuypers]

Thanks a lot for the fast reply John!

[Bucksears]

Bumping this old topic:

I built the GEOFex tester with the momentary switch in order to test a bunch of silicon transistors for some Big Muff variants; do I need the switch to measure the gain, or do I just insert the transistor?
I did switch the pos/neg leads from the power supply and reversed the red/black leads from the DMM.

Thanks,
- Buck

[slacker]

Yeah you need to press the switch to measure the gain. Without the switch pressed you're measuring the leakage, which should be virtually zero for a silicon transistor.

[Bucksears]

I thought silicon devices shouldn't have leakage?

I basically set it up on a breadboard, and get one reading when insert the transistor, then another when I press the switch.
Without all of the explanation of what reading does what, is there a basic formula to follow to determine hfe?