# Solenoid capacitor circuit for paintball gun

Recently my electric paintball gun broke so i decided to come up with my own circuit. I tried to reverse engineer the one my gun had but it was covered in black glue...

I have been trying to design a circuit that will power a solenoid to fire my paintball gun. My problem is that the capacitor does not charge fast enough after being discharged to fire the gun. The capacitor the gun uses is a 6800uF electrolytic cap and the battery is a 9.6 volt alkaline battery specifically for my gun. The solenoid has a resistance of about 1.2-1.5 Ohms. I did the calculations and you need .313 Joules of energy in order to fire the solenoid. Normally i would like to use a regular 9V alkaline battery instead of the 9.6 one. Either way, I'm having trouble keeping the capacitor charged at 9 volts so that it fires the solenoid repeatedly without dropping the voltage too low.I know its possible because i used the circuit from my friends gun to fire my solenoid while measuring the output of the capacitor. The voltage would never drop below 8.8 volts if i used the 9 volt battery. Any idea on what i can do?

[ I included a picture of the original circuit my gun had. It looks like they have 1 IC, 2 transistors, a few caps and resistors and 1 or 2 diodes.1[The other side just has a button a capacitor and an led [2]]

• What kind of transistor did you use to charge the capacitor with? A bjt? a mosfet? What is it called? Or did you salvage it from the gun? Jul 12, 2017 at 6:34
• Instead of pulling teeth I'd love to see that circuit you were trying to design. - You'll get much more help that way. Jul 12, 2017 at 7:02
• Ok first time using the software from here, but heres what i have tried. I have also tried it without connecting the P channel mosfet and just having the battery connected to the capacitor. Jul 12, 2017 at 7:37
• The trigger signal, what kind of signal is that? Is it a simple physical switch or is it some IC sending pulses? And V3 looks.. fishy. Try out this if you want to play around with circuits in the future btw. I strongly recommend this: tinyurl.com/y84stbey Jul 12, 2017 at 7:56
• Yes an IC will control that and will control V3. well i have a p-channel for V3, would that not work as a high side switch? what if i just take that off? Jul 12, 2017 at 8:08