I am using a darlington buffered op-amp to drive a solenoid motor at variable voltages (for variable speeds of actuation). Here is my circuit as it is now:
I am wondering which of the two flyback diodes (from coil to GND and coil to VCC) are necessary to drain flyback current from the solenoid, or if perhaps a resistor across the solenoid is necessary.
The diode from the op-amp output to the coil is to prevent flyback from interacting with the op-amp output. This one I am certain is necessary from hands-on testing.
Normally I see this as a flyback circuit:
But this is notably different from my case, sense it works by connecting and disconnecting the solenoid from ground, whereas my circuit provides a variable voltage at the input. I am wondering what I need to change in the flyback protection setup to account for this difference. Thanks!