## Germanium (or sillicon) BJT transistors leakage measuring pr

Stompboxes circuits published in magazines, books or on DIY electronics websites.

### Germanium (or sillicon) BJT transistors leakage measuring pr

Hi,
I was trying to measuring transistors leakage and HFE by this method: http://www.geofex.com/article_folders/ffselect.htm
I have two problems:
1. first reading of voltage is highest, then voltage on multimeter is lowering. I don't know if first or last (after few minutes) reading is right.
2. Even if I get highest valu of voltege, HFE calculating by this method is a half of HFE that shows my multimeter.

What I am doing wrong?
mailoszyarr

Posts: 3
Joined: 10 Sep 2014, 19:43
Has thanked: 0 time
Have thanks: 0 time

### Re: Germanium (or sillicon) BJT transistors leakage measurin

for me it works for pnp but not with npn
boby6kiler

Posts: 35
Joined: 24 Feb 2014, 10:04
Has thanked: 6 times
Have thanks: 9 times

### Re: Germanium (or sillicon) BJT transistors leakage measurin

boby6kiler wrote:for me it works for pnp but not with npn

For npn you simply flip input voltage polarity on both 9v supply and your dmm

mailoszyarr wrote:Hi,
I was trying to measuring transistors leakage and HFE by this method: http://www.geofex.com/article_folders/ffselect.htm
I have two problems:
1. first reading of voltage is highest, then voltage on multimeter is lowering. I don't know if first or last (after few minutes) reading is right.
2. Even if I get highest valu of voltege, HFE calculating by this method is a half of HFE that shows my multimeter.

What I am doing wrong?

1. 1st reading must be measured without the load (2.2mOhm). 2nd reading is done when the load is applied. Second reading is always higher that the first one

2. it's okay, it means that your transistor has a lot of leakage, it confuses your DMM, because it was made for modern silicon transistors, that don't have leakage compared to old germanium.

plush