Inductive kick as a pulsed power source?

Thread Starter


Joined Dec 17, 2007
Can it be done? Contemplating a homebrew coilgun as a birthday present for a friend. Pulse rated caps in the appropriate voltages are way outside my budget. How would I calculate the voltage of the kick, so that I can have properly rated SCRs?


Joined Jun 30, 2006
There are a dozen coil gun sites on the web with instructions. You enter the realm of spooky with high power magnetic fields.

Thread Starter


Joined Dec 17, 2007
Yah, I was rather getting that idea. Moving from simple audio and timing stuff to bizarre high voltage realms is weird. Most of the Gauss gun sites I came across want you to use HV pulse caps, though. I will have to do more research.


Joined Oct 19, 2007
I am pretty sure you can use an ignition coil salvaged from a car to generate tens of thousands of volts of electricity in short bursts with relative ease.


Joined Jun 19, 2007
^ very true.

~12V in, ground controlled. A car at idle needs ~15Kv and the coils usually have no issue producing up to 40Kv for high load/resistance situations.

Kv to Ms output has proven to be somewhat proportional. I.E. 15Kv @ idle yields a 4ms spark after going thru all of the secondary circuit and and overcoming high combustion chamber temperatures/pressures. At 40kv it would only yield a 1ms spark. A longer coil saturation could help if you need a longer lasting spark.


Joined May 16, 2005
Inductive kick will indeed generate high voltage. Nice little arcs! I don't know about high power though... If you put a load on your kick, won't it reduce dI and increase dt?

Thread Starter


Joined Dec 17, 2007
While 15 kV sounds very nice in theory... there is no way on earth that I can afford an SCR rated for 15 kV, no matter what the current. I was more hoping for some hint towards inductor construction. I am probably thinking something in the area of 400 - 600 V. I am still very much in the design phase, so I am open minded, but I am not talking about anything other than a cool toy, really.


Joined Dec 24, 2007
With an ignition coil circuit, you control the 12v input to the coil which controls the 15 Kv output... So really you only need a relay\transistor\etc... that can switch 12v

If you use a relay, make sure you use a solid-state relay so there is no mechanical bounce...

Triggering could be handled by a monostable 555 timer to prevent trigger bounce

I need a ~600V SCR for a camera flash ignition circuit for pyrotechnics... I have a good camera flash circuit made, and a decent RC circuit, but I need to find an SCR to switch the 330-500V output of the flash cap...