Page 119 - Testing Electronic Components
P. 119
Transistor Heat sink
The heat generated by current flowing between the collector and emitter
junctions of a transistor causes its temperature to rise. This heat must be
conducted away from the transistor otherwise the temperature rise may be
high enough to irreparably damage the P-N junctions inside the transistor.
Power transistors produce a lot of heat, and are therefore usually mounted
to a piece of aluminium with fins, called a heat sink.
The heat sink draws heat away from the transistor, allowing the transistor
to handle more power than if there were no heat sink. Low power signal
transistor; do not normally require heat sinking.
Some transistors have a metal body thus a mica sheet has to be used to
prevent the body from touching the heat sink.
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