GMC-I Messtechnik GmbH
21
B
= Basis
C
= Collector
E
= Emitter
Valuation of a diode and/or the diode path of a transistor
A diode and/or a transistor functions when the indication on the V, A
scale during a measurement in forward direction is smaller than the
indication during a measurement in reverse direction. The qualitative
behaviour and the technical data of the semi-conductor can, however,
not be judged by the degree of deflection; mainly the current gain of a
transistor is not picked up. When measuring in reverse direction, the
multimeter indicates the voltage on the diode path on the k
x 10
range (1 V for full scale value
).
The reverse current flowing thereby is
the difference between the full scale value (graduation 100) and the
indication
.
One graduation corresponds to 10 mV and/or 22 nA.
A diode and/or a transistor is interrupted when
or the same value
close to
is indicated on the
-
scale in both directions (insulation
resistance)
.
A diode and/or a transistor has a short between the con-
nection electrodes when 0 or the same value close to 0 is indicated on
the
-
scale in both directions
.
Measure-
ment
Diode
Transistor
in
on socket
on socket
on socket
Forward
direction
A|
A|
A|
Reverse
direction
A|
A|
A|
A
K
E
B
C
NPN
E
B
C
PNP
