Page 123 - Testing Electronic Components
P. 123
• Whenever replacing output transistor nut-bolt should not be too tight
or too loose.
• Horizontal output transistor, with integrated diode should be replaced
with the same type of transistor.
Transistor Testing and Identifying the Leads
A transistor can be checked out of circuit with any of the many different
transistor testers on the market. The suspected transistor can be check out
of the circuit with resistance measurement (Ohms range) from the
analogue multimeter. Use ohmmeter scale to detect a leaky, open or
shorted transistor. I do not encourage testing transistor with digital
meter as Ive encountered many times that a transistor test good with
digital meter but failed using the analogue meter.
Checking transistor with an analogue multimeter
An analogue multimeter can be use to perform a basic test on a transistor;
the diagram in Figure below will help you to identify the base, collector
and emitter leads for commonly used transistor. You should refer to the
transistor data guidebook if you are in doubt about the connections of a
transistor. But if you are about to use a transistor of an unknown type, i.e.
NPN or PNP, the following simple test will give the answer. It will also
allow you to check a transistor if it is leaky, opens or shorted.
123
