I am working on a coil gun and am going to add another coil but switching is a problem i want to use an IR led and receptor but dont no how to build a circuit that once the beam is broken the circuit will be completed and power to go to second coil.
The trouble is, it can't be left in standby for more than a few seconds as the capacitor will discharge through R2 to R4.
If this a problem a different, and possibly more complex, approach will be required.
EDIT:
I've come up with another idea. It doesn't have such a high leakage current but it requires a pulse transformer. Fortunately it's easy to make a pulse transformer with a ferrite bead and some hookup wire.