Curious to know if anyone can advise the correct diode (D2) to use to prevent a surge back when the solenoid releases. I'm using a 24vdc 5-way pneumatic solenoid to manipulate an actuator. An Arduino Due with an ESP32 triggers a "MOS Transistor Driving Controller Module FET Trigger Switch Drive Board" which separates the 5vdc from 24vdc. This is a picture from an old post with @KeepItSimpleStupid that closely matches what I'm setting up.



Thanks!

 

How much current does the solenoid need?

 

How much current does the solenoid need?

The label indicated 24VDC 4.8W:

 

It looks like 200 ma in the load, so you can use a fast diode with a slightly higher current rating and greater than 24V PIV. I would use a 1N5819.

 

If you want it to release really fast, then a 24V zener (or transorb) in series with the 1N5918 would speed it up, but it would require a MOSFET rated >50V (which you have)

 

If you want it to release really fast, then a 24V zener (or transorb) in series with the 1N5918 would speed it up

Note the the Zener or Transorb must be connected in opposite polarity to the diode (anode towards the positive voltage).