I was wondering how to measure the gain of BJT's. I'm messing around with different fuzz circuits and I've just been plugging different trannies in to see how they sound, but have no idea what gain ranges I'm messing with. I've looked at data sheets, but some of the ranges are pretty broad.
I was hoping there was a circuit I could breadboard and figure this out.
A lot of DMMs have built-in transistor test functions. It's nice because you can use that to figure out if a tranny is PNP or NPN and also figure out which lead is which. And of course, it measures gain.
I got a fluke without that function, and a little cheapie with that feature, but it doesn't work :(
I need to get a cheapie that does work
There's the dca55. There's also a thing I've seen on here that was just a small screen with leads
The parameter you're looking for is hFE, which is a term you'll see in datasheets when looking for gain ranges.
Basic reading:
http://en.wikipedia.org/wiki/Bipolar_junction_transistor#h-parameter_model
That should give you enough info to google further information on your own. You could also probably suss it out by reading the Technology of the Fuzz Face article, which goes one step further and tells you how to read leakage for germanium transistors.
Every multimeter measures current. You shouldn't need to buy a more expensive one that measures a transistor on its own unless you're testing tons of transistors, because you only need a breadboard and a few resistors.
Quote from: jighead81 on November 23, 2014, 02:51:53 AM
I got a fluke without that function, and a little cheapie with that feature, but it doesn't work :(
I need to get a cheapie that does work
A lot of the time I find the sockets on those cheapie transistor testers are awful and if you push it in and wiggle it, you might get it to work (although that advice might not work out of context).