Russian Transistor leakage testing help

[garfo]

Hey, I've build a Transistor leakage and hfe device from Guitar FX layouts.
The transistors I'm testing are old Russians MP39's.
The readings I'm getting are a little bit low, but I'm not sure how to make the conversions or even interpretate the readings.
Multimeter was set for Voltage (2volts) for measuring leakage and hfe, but I'm not sure this is the way to go.
I've tested two already: First one: Leakage: 0.030 mA; Hfe: 35
                                   Second one: 0.050 mA; Hfe: 37 
I took the reading in voltage and divided by 2.472(K) whitch is the value of the resistor I'm using. The result is supposed to be in mA.

I'm not sure what this means. How do I know if it is leaky or not!?

Thanks, hope someone with more knowledge can help

[nieradka]

Those numbers look right to me. MP39s Ive tested have had leakages close to 0, they are low noise parts. And leakage is supposed to me in uA, not mA, right?

[Bret608]

I found an Excel spreadsheet that was done by Duhvoodooman over at the BYOC forum. I've been using this with good results. Here is the link:

http://www.byocelectronics.com/board/viewtopic.php?f=9&t=38231&hilit=transistor+calculator

Basically, you enter your battery voltage, your actual resistor values from your tester, and then your readings. I had to look at it side-by-side with the instructions that came with the GuitarFX layout a couple of times to make sure I was understanding it correctly.

Your numbers do look believable to me. These would be low leakage and low gain as well. For example, on the one with 35 hfe, you could express the current leakage as 0.030 mA or 30 uA. Something like 0.30 mA or 300 uA would be considered high leakage.

[EBRAddict]

Your leakage values of 0.03mA and 0.05mA (30uA and 50uA) are reasonable. I've seen it claimed that anything under 200uA is usable but with Ge I would make sure to try them out before dismissing them.

I've bought batches of Russian Ge transistors and found the leakage to vary but the median on the NPN was around 90uA and the PNP was around 50uA. If you have some low-gain PNP check out the Sziklai Rangemaster page on Smallbear. I've had good luck using them in that configuration.

[garfo]

Thank you guys. The ones that tested arround 35/45 hfe are Mp39b's.
I have other MP39's that are way lower gain and the leakage is arround the same.
I wasn't sure I was making the mA/uA conversion the right way, .
but the numbers look alright then.
Thank you very much for helping. It was the first time I've tested the trannys in a propper way.