Putting the fun into Electronics

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Have you ever pulled off a spark plug wire to check the spark coming out.  I got to thinking if I had a circuit that would duplicate the ignition system, it might be kind of fun to play with.  While sparks are jumping all over I could dare anyone to test it out.  There might be some kind of medical use for one of these.  Could it keep cows or other animals out?

I built this circuit which can drive an auto ignition coil to make a nice big spark every couple of seconds.  The time constant is controlled by the 1K resistor and the 470uF capacitor.  When the capacitor charges up enough then the output transistor turns on and back off again making a big spark.  The charge from the capacitor gets dumped into the coil.  If you lower the 1K resister a whole bunch you can get almost a continuous stream of sparks which makes it even more fun at parties. Actual testing showed it needed more current to drive an electric fence to completely keep cows out of the garden but with it's higher voltage may work better for smaller arias where dogs and cats are a problem.  This my not be used by anyone with a bad heart condition or for torturing animals or man.  If you build one of these, I'm in no way responsible for it's use.