[AMRadio] Testing High Voltage Diode Blocks

Bob Deuel k2glo at jkasystems.com
Sat Jun 7 13:59:04 EDT 2008

There have been some comments about H.V. diodes not testing but seem to be ok. I assume that people are testing them with the diode function of a digital multimeter. 

Typically, a H.V. diode has a number of diodes in series within it which makes it have a higher voltage drop than a normal diode. Because of the higher voltage drop, a digital multimeter show them as defective. A crude and simple "go - no go" way of testing a H.V. diode  is to hook the diode block in series with a 120V lamp and apply 120V to the diode - lamp series combination. If the lamp does not light, the diode is open. If the lamp lights at about half brilliance, the diode can be assumed to be good. If the lamp lights at full brilliance, the diode can be assumed to be shorted. Obviously, be very careful when working around line voltage.

Bob, K2GLO

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