Help! Almost killed by exploding capacitor! What did I do?

[TinselKoala]

Now for switching.
You clearly want as fast a "rise time" of your input pulse to the coil, as possible. This means ordinary transistors or mechanical switches are out. You could try MOSFETS or Darlington pairs or IGBTs, but it sounds to me that at your current (pun intended!) level of experimentation you could be using a spark gap for switching the power into the coil. Even though your voltages are low. The rapidly-closing contacts of a stout relay will approximate a spark gap at the power levels you are interested in, I believe. When you get to higher voltages you can use an overvolting air gap, fixed at a spacing that will give the desired voltage. When you get to even higher power levels I can tell you how to make a TAG (triggered air gap) for switching very high-energy cap discharges into a coil.

So, I think that discharging the right cap, through the right choke and resistance, into your coil, using a stout relay or spark gap for switching, will be the way to get the current level you need into your coil.

[konduct]

I would bet the power source was AC and the capacitor was an electrolytic, the P/S output would pop the cap, especially if it was close to a harmonic of the resonant point of the cap.

It was a DC power source...I just had the cap in backwards because I'm a newb...thought it was pos in pos out rather that neg and pos terminals.

[Thaelin]

   Back in High School a few of us plotted to "surprise" our teacher a bit.
We hung a 150uf 450v cap outside one of the windows and hooked it
up to the line voltage via bridge rectifier, backwards of course. As the class
got underway and he was facing the blackboard, the on switch was flipped.
To our surprise as well, it went off as loud as a shotgun blast. Cracked the
glass and brought the fire dept/police in a hurry.

We all got sent home for the day with a letter to the parents. After a good
rear end warming, I went to bed.

So do be very careful with them.    No matter, it was fun to see the look on his face.

thaelin

[spinner]

It was a DC power source...I just had the cap in backwards because I'm a newb...thought it was pos in pos out rather that neg and pos terminals.

High, C.. Konduct!

Yes, I've expected something like this....

My original thought was - either you missed the el.cap. polarity (80%  chance), or your "AC/DC" was well beyond 12V (15%) - (that was the second most logical thing, expressed by many members)...
Or, the cap/electrolyte was damaged (3%). Assuming the rest of the circuit was as described...

Ha, I left the 2% for the unknown effect, "magic"....


It sure was interesting to read all the suggestions!

Cheers!

[Bulbz]

Help! Almost killed by exploding capacitor! What did I do?

Remembered to duck, I hope 

I don't think it's such a good idea to hook up capacitors of different volt ratings though. I done the same thing years ago, and noticed the smaller capacitor started to heat up.

It may be the same as hooking up a 1.5 volt AAA battery to a 24 volt leisure battery.