Author Options:

Coil / Gauss Gun Question Answered

Hi, I want to build a coil gun and i was wondering whether or not this design would work? For the battery i was thinking of using a 9volt, the multimeter is there so i can know when the capacitors are  fully charged, and the two switches on ether side of the battery is so i can disconnect it before i fire.


sure that could kind of work, you typically need higher volts, like above 200 to make an effective coilgun. you also need protection diodes to protect the capacitors from back emf. Also, depending on the power levels, your swtich may get fused shut when fired.

well i'll be using about 30 desposable camera caps in the 100uf 300v-350v range i got free from the store, so would my switches be fused shut by that? And where/how would i wire in the "protection diode"?

That'll most definitely fuse your switch shut. Typically you need an SCR, google SCR and coilgun or railgun for a complete answer. However, if you just want a quick and dirty method, just use like a homemade heavy duty switch (beware of the high voltages).

In order to actually charge the capacitors to 300 volts, you need to hook up a 300 volt powersupply to them, ie the circuitboard in the disposable camera. Hooking up a 9volt battery driectly will only charge the capacitors to 9 volts (which at 3000uF will still make a little spark).

Ive never built a coilgun, but since electrically its similar to a relay/solenoid/motor, i think you can just hook up a diod (that can withstand at least 400 volts) backwards in parallel to the coil, so that it does NOT conduct when the capacitors are charged. In your drawing, the diode arrow would be pointing to the left

forgot to add link to pic


updated pic, im guessing more like this?

not sure if i got the power supply in right tho, its suppost to be in parrallel with the cap bank the same way it was before you take out the individual cap right?