I have a couple basic questions about the attached schematic for creating a cap dump (from p. 47 of the intermediate handbook).

A switch is shown (I've circled it in red and labelled it) between the positive post of the run battery and two other circuit branches, one going to the top of the main coil, the other going to the 555 chip circuit. Iím assuming thereís no physical switch there, and that itís just an area that functions like a switch. Can anyone confirm this for me? I want to make sure if thereís a part I need to buy, I get it.

Incidentally, the reason I can conceive of it as a virtual switch is that when the battery is pulsing current it would ďcloseĒ the return path from the main coil to the battery positive, and when the battery isnít pulsing, it would ďcloseĒ the return path for current coming from the 555 circuit. Is this correct?

Another question is about the 7812 voltage regulator. Iím assuming the leg shown on the top, closest to the number 7812 is input, the one going out to the right is output and the other is ground (I've labelled them such to clarify my question). Is that correct?

Thereís a diode between the recovery coil winding and the capacitor and voltage regulator. Itís a single diode as opposed to a bridge rectifier which is in the older schematics. Would a 1N4007 work? If not, what diode should I put there?

When the magnetic field in the inductor collapses, Iím assuming the back EMF goes out through the recovery coil along with the radiant spike (instead of going back into the run battery). Is that right?