[SOLVED] Selecting the proper a diode for Forward Current If(AV):

[Gary Murray]

Hi All

A newbie question. I need to select a diode for circuit protection when connecting a solenoid which has a load of 400mA. When selecting a diode what forward current rating should I select. Should it be for 400ma or a great value. Is there a rule of thumb that should be applied:?:

 

[betwixt]

If it is for circuit protection I assume it is across the solenoid and wired so it isn't normally conducting so the current rating doesn't have to match the load. It's purpose would be to clamp the reverse voltage from the solenoid as the voltage is removed from it so it would only conduct for a few milliseconds and it would never have more than say 1V across it. You could probably use a small diode such as the common 1N4148 but I would err on the side of caution and use a 1N4001 to 1N4007 type which are very inexpensive and easy to obtain. The only critical rating is the PIV (peak inverse voltage) which has to be more than the voltage the solenoid operates at.

Brian.

 

[Gary Murray]

thanks a million