How to measure "real gain" of ge trans. w/ a DMM

[FenderTyler]

I just started building effects and just finished my first fuzz circuit (fuzz face of course). I am trying to learn how to measure a germanium transistors real gain with an DMM. Small Bear has some directions of how its done but i have no electronic experience and kind of need a step by step guide. I have learned a whole lot just by reading on this forum and i know this would be the place to learn how to find trans. real gain. If anyone can help out it would be greatly appreciated so that my first fuzz can sound its best.

[jpm83]

Here is a link that I used when I was making my fuzz face. http://www.geofex.com/Article_Folders/ffselect.htm

Janne

[smallbearelec]

I sometimes get this kind of question respecting the How-To article. I suspect that what you really need is some help learning to read voltage, resistance and current on your DMM, and that's beyond the scope of the piece. In a very few cases, the instruction book for your meter may give you some help. Beyond that, set the instrument to one of the voltage scales, measure a couple of batteries and see how the display looks. Likely, you'll find that a battery that says 9 volts really isn't! Then measure a few resistors on the resistance scale. Now connect one of your known resistors to the battery, measure the current through it, and see how the display reads. For example:

A battery of 9.1 volts in series with a 10K resistor will give a current of 9.1/10,000, or .00091 amps. Usually, we would refer to this as .91 milliamps or 910 microamps. Your meter may show it either way, depending on how the scaling has been designed.

I hope this helps you some in using your DMM as a microammeter in testing the gain of germanium devices. The Hfe scale of your meter, if it has one, will not work correctly on such parts.