Page 149 - Testing Electronic Components

touching the Anode pin) and you will notice the meter’s pointer will kick
as shown at the picture (low resistance).

Removing the black probe from
the GATE pin (the black probe
still touching the Anode pin)
you would noticed that the
resistance continues to be there
(low resistance). This is due to
the conduction of SCR as the
meter battery is usually able to
supply current more than the
holding current.

If at this stage you removed the
black probe from the Anode
pin and connect it back, the
pointer will dropped back to
infinity (high resistance). If the
SCR could hold the resistance
then the SCR is considered
good. If it can’t hold then the
SCR is faulty.

Conclusion- Practice testing SCR more often to see how’s the result like.
Try some different part numbers and power SCR-and if the resistance
don’t hold using X1 ohm, you may try X10 ohm and etc.

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