diode check


Old 02-18-07, 04:48 AM
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diode check

how do i check the diodes on my welder. i have tried but i do not think i am doing it right.
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Old 02-18-07, 08:00 AM
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first, to check any electronic componant accurately, it must be isolated from the circuit.

then, to check a diode, you simply use an ohm meter. Since a diode allows current to pass in one direction only, you simply test the diode in forward and reverse bias with the ohm meter (it deosn;t matter which is which actually).

It will read infinate resistance one direction and near 0 ohms resisitance in the opposite.
Old 02-20-07, 04:29 AM
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Originally Posted by bacon View Post
how do i check the diodes on my welder. i have tried but i do not think i am doing it right.
A simple check is with an ohm meter. Measure the resistance of the diode, and then reverse the leads and measure the other way. One reading should be at least 10 times the other way. Neither direction should be a direct short (zero ohms) or a complete open circuit (infinite resistance). Most of the time, the diode must be removed from the circuit to obtain an accurate reading because the other components in the circuit will affect your reading. As an Instrument/Electronics Tech (retired) I usually just replaced suspected bad diodes or transistors rather than bother with testing, but then, we had a large stock available in our store room.
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