TC1 users, some questions for you

[MBFX]

Bumping this old thread to chime in that my TC1 tester doesn't read JFETs reliably - 2N5485s read as either an inductor or a resistor, and only two of the pins are being read. I don't think it provides enough negative current to open the gate!

 

[joelorigo]

I recently got one of these and tried some various transistors. My questions is that if I leave a transistor in and test repeatedly, the hfe readings go lower and lower. Is this normal?

 

[benny_profane]

I recently got one of these and tried some various transistors. My questions is that if I leave a transistor in and test repeatedly, the hfe readings go lower and lower. Is this normal?

Is it Ge? If so, it will read higher if you’ve raised the temperature by handling it.

 

[andare]

I recently got one of these and tried some various transistors. My questions is that if I leave a transistor in and test repeatedly, the hfe readings go lower and lower. Is this normal?

In my case both leakage and hfe go down and eventually settle. It means the transistors are cooling down. Don't handle them with your hands, use tweezers. Or wait.

 

[joelorigo]

Ah I see. I was using both silicon and Ge.

Thanks!