Page 144 - Testing Electronic Components
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(collector) pin and the red probe to both side of the HOT one at a time,
the pointer should not kick (means no reading). If you get a reading when
the read probe touches on either one of the pins at the right (base) or left
(emitter) chances are high the HOT had shorted. You need to remove the
HOT from the board and retest again.
The above method only applies when checking HOT on board. Checking
HOT off board is completely different from the above.
Testing HOT off board
There are two types of HOT i.e. one is without damper diode while the
other one is with damper diode. How do we know if a particular HOT
comes with damper diode or not? Its easy, check from the semiconductor
data book or searches the internet. Checking a HOT that does not have
the built in damper diode is exactly the same when you are testing a
NPN bipolar transistor (please refer to the testing NPN bipolar
transistor).
If the HOT have a built in damper diode, then you have to follow this
way to test it. Set your analogue meter to X10 K Ohm and place the black
probe to centre (collector) pin. Now, moving the red probe touching the
first (base) and the third (emitter) pin and it should not show any
readings. If you get even a single reading the HOT is considered shorted.
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