Here is my schematic so far for my solenoid driver board. The PWM control took up too much space to include on the board due to the limitations of EagleCad's freeware. Each control circuit has two inputs, one for the trigger and one for the PWM power control. I might add in a way to disable the single pulse generator so that you can just trigger it on or off if there is room on the board. However, I can only think of a few instances that would require it as most solenoids will burn out if left on too long. I will post the EagleCad files including the board layout when I am finished.
Last November, I fried my 'lab power supply' that I made from a computer PSU. I was testing my solenoids and the stress was just too much for the PSU. The mistake I made was rapidly turning on and off my solenoid which likely resulted in voltage transients (spikes). Since the PSU does have a current limiter, it was likely the constant voltage spikes that caused the damage. There are various methods to suppress voltage transients such as by-pass capacitors and zener diodes. In particular solenoids and other inductive loads experience these voltage spikes, hence my no longer functioning bench power supply. ATX Breakout Board I could have just rebuilt the same power supply by adding binding posts etc to the PSU housing but after searching the internet an ATX power supply breakout board seemed a popular option. The main advantage compared to my old power supply was the addition of fuses on the outputs. The extra safety this provides is perf...

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