The basic principal of a ignition coil (or ignition transformer). Unfortunately there's no sparkgap in Everycircuit, so I had to do it with a lamp (the voltage of the lamp is low, so it will burn on the voltage peak). The top switch is the "ignition switch" which is normally switched by the carkey. Switch it on, and a current will flow to magnetise the coil. Then hit the bottom pushbutton very shortly. By doing this, the primary coil will peak to about 200-300 volts. On the secondary coil, this will be 20.000-30.000. This will be the voltage that will spark between the sparkgap. Enjoy!
The zener diodes are placed to block the (start-up) peak voltages which enlighten the lamp. It's just a detail, and is NOT placed in a real ignition coil circuit.
