Hello everyone, so I am trouble shooting a 5v solenoid not working when plugged to an external source, and when I use my DMM the voltage across the diode/ the solenoid is around 2.6V. The diode is a 1n4007 and the transistor is a tip120. Below is the circuit schematic, please ignore that its shown to be powered by arduino. It isnt, it has a 2 pin barrel jack (1 for -ve and 1 for +ve).
So my question is do I need to supply more than 5v to the solenoid because of voltage drop of the diode?
Thanks in advance.