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Fly back diode failure

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Junior Member level 2
Feb 21, 2022
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I am using a 1N4007 and 53ohm resistor as flyback circuit for operating solenoid coil
now I am facing problems with failure of the diode, diode has found open in multiple boards
what could cause this problem ?, is there any equation selecting the resistance value ?
or is it problem with diode itself, I am using MIC make 1N4007


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That diode should work perfectly unless your voltage/power readings for the circuit are WAY off.
thanks for the reply
we are using the above circuit to drive a 24V 2.5W AMISCO , when I checked coil resistance
after failure it shown the normal value, is there any chance for over voltage or current if there is no coil damage ?

Besides the point, that the 56 ohm resistor is effectively useless but doesn't disturb, I'd consider the circuit as just standard. I don't see a way to damage the diode by electrical means.
--- Updated ---

Possible failure scenarios are e.g.:
shorted solenoid coil -> transistor damage
massive supply overvoltage -> transistor + solenoid damage
supply reversal -> R103 burn, without R103, diode and possibly transistor can be damaged
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Diodes usually fail shorted if the ratings are exceeded, which cannot really happen in your circuit.

Its much more likely you are the victim of a batch of sub standard diodes from a third world country.
Suggest you dump the lot, and buy some more from a well known reputable component house.
A reputable seller will have full ISO traceability and paperwork right back to the manufacturer.
If you buy direct from China, it may be o/k or maybe not.
Sadly, this type of thing is becoming a lot more common.

the only thing i can think of is , is the diode the right way round in the actual cct?

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