Velleman DCA75 - Manual (Page 17)

Atlas DCA Pro User Guide December 2012 – Rev 1
Page 17
VBE=0.270V
at IB=5.00mA
ICLeak=0.177mA
Collector Leakage Current
The collector current that takes place
when no base current is flowing is
referred to as Leakage Current.
Most
modern transistors exhibit
extremely low values of leakage
current, often less than 1µA, even for
very high collector-emitter voltages.
Older Germanium types however can
suffer from significant collector leakage
current, particular at high temperatures (leakage current can be very
temperature dependant).
Leakage current is automatically taken into account for the gain measurement
(unlike many multimeter’s gain measurement that can be fooled by leakage
current).
If your transistor is a Silicon type, you should expect to see a leakage
current of close to 0.000mA unless the transistor is faulty.
The leakage current of germanium transistors can vary a large amount
with changes in temperature (roughly doubling with every 5°C
increase). Even the warmth from your fingers can alter the leakage
current of a germanium device. Conversely, a cooling transistor (after
a little handling) can result in a falling leakage current measurement
over the period of a few seconds/minutes. This is completely normal.
IC
Leakage
IB = 0