[sdiy] Ge transistor tester weird results

Gordonjcp gordonjcp at gjcp.net
Tue Feb 8 13:25:10 CET 2022

On Mon, Feb 07, 2022 at 06:46:11PM +0100, cheater cheater via Synth-diy wrote:
> Hi all,
> I recently bought and tested a few Germanium transistors in my small
> semiconductor tester and I got weird behaviors.

Yup.  That's why no-one makes or uses Germanium transistors any more.

If you kick it oldschool and measure them with a multimeter in a test circuit, you'll probably find that they all have a leakage current measured in milliamps even when they are fully cut off, and a maximum current about five to ten times the leakage current.  If you see a real genuine hfe of more than about 30 then you're measuring it wrong.

Most of the deep weirdness you're seeing with things like an hfe over 250 is probably it grossly miscalculating from a huge leakage current.


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