Testing AC128 for gain

[gutsofgold]

I'm using Steve D's method for testing gain of germanium transistors. I hook everything up as shown directly with alligator clips and I get .28mA for my leakage current. Then I connect the 1M resistor from the Base to the Neg battery junction. As shown:



I get .79mA Subtracting the two and diving by my base current of 9.11 (due to a 9.11 v battery and 1M resistor) obviously does not give me a very substantial number. I'm using a Radio Shack DVM set to DC mA with fresh batteries in it. And like I said my battery is a full 9.11v. What gives?

[R.G.]

You have a units problem. 0.28ma is the same as 0.000280A or 280microamps (uA). 0.79ma is 790uA.

Likewise, 9.1V/1megohm = 9.1MICROamps = 9.1uA.

So you get (790-280)/9.1 = 510/9.1 = 56

[gutsofgold]

Ahhh milli micro milli micro ... I need to remember these things! Thanks.

Is it safe to assume that a transistor that gives no leakage or collector current is a dud? The AC128's I am testing have never worked right in a Fuzz Face I built even though I bought them from AMZ. I didn't think I would get a dead one from him.

[SUPER VELCROBOY]

Ahhh milli micro milli micro ... I need to remember these things! Thanks.

Is it safe to assume that a transistor that gives no leakage or collector current is a dud? The AC128's I am testing have never worked right in a Fuzz Face I built even though I bought them from AMZ. I didn't think I would get a dead one from him.

you probably didn't do it right. The Germanium AC128 should have some leakage usually low 100 uA to all the way high 700 uA that you throw away (usually). Most people seem to keep anythign under 300.

[gutsofgold]

Well I'm officially not getting any current through these AC128's. Is it possible I somehow damaged them? 
Maybe the Collector and Emitter touched at some point?