Peak Atlas DCA Pro
User Guide
June 2019
–
Rev 1.7
Page 17
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,
even for very high collector-emitter
voltages.
Older Germanium types however can
suffer from significant collector leakage
current, particular at high temperatures
(leakage current is very temperature
dependent).
Leakage current is automatically taken into account for the gain measurement
(unlike many multimeters
’
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. Values less
than 10
μ
A are not displayed due to resolution limits.
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 significantly 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.
