The coils on the coil gun have to be wired based on the schematic shown above. An SCR (Silicon Controlled Rectifier) or thyristor is used to control the high voltage supplied to the coil, it acts like a switch. I used a 50A rated stud type SCR, 50RIA120, smaller SCR's like the TYN616 can also be used if 5 or 6 of them are connected in parallel as each provides a surge current rating of 200A. Conventional switches or relays cannot be used since they usually burn the contacts in them due to the high voltage and current.



The inner workings of an SCR are simple. When a voltage is applied to its gate via a small battery, the diode is activated and the cathode and anode can be connected to the coil just like a normal diode. A switch that controls the gate voltage being applied to the SCR essentially controls the current going to the coil and acts as our trigger for the coil gun. Even if you have a lot of capacitors hooked up in parallel without an SCR capable of handling high current, you will not be able to supply the full power. High gauge copper wires should be used while connecting the capacitors and the coils. All connections and terminals should be properly insulated to prevent yourself from getting electrocuted. When choosing an SCR, choose one with a high value for "Surge Current/Itsm". The datasheet for this SCR can be found at: SCR Datasheet.