Transistor behaviour testing

Started by Mcentee2, January 03, 2025, 01:21:10 AM

Previous topic - Next topic

Mcentee2

It seems most people test transistors for hfe and leakage, but does anyone test and sort based on any other parameters ?

I have seen references to Mike at Analogman resting for 4 parameters, but can't find what they are (assume two are hfe and leakage at a set DC!)

I don't know, but am thinking along the lines of impedance/capacitance that might affect frequ ncy response - this is assuming each transistor varies a lot.

I think Noise would be one but that would be just via a listening test anyway rather than pre-build sorting.

I can also see that even if these could be easily tested it's an easy trade off to stick with just hfe/leakage, then just build it and listen :)


camelfish

I test a lot of transistors for pedals and resale.
The other 2 and are just as important if not more so..
Noise level and stability.
I check noise by ear in a high volume Rangemaster circuit,
Stability is by monitoring in the circuit required - checking bias voltages over time.

mozz

#2
You can also measure capacitance and impedance. Also A.C. beta.  I would think bias voltage would be pretty stable if kept at a constant temperature. I love stuff from the germanium era.






  • SUPPORTER