circuit-designinductanceinduction
I'm curious why an ignition timing light needs to connect to the battery to work.
I may not be fully understanding how they work, but I'm guessing there's an inductive pick up and that illuminates the bulb.
So couldn't just that inductive kick be enough to light the bulb?
Passerby and Russel; thanks for the feedback. It turns out what I thought was a thin piece of foam spacing with adhesive on it was actually a thin sheet of metal; I would assume lead. This explains the interference and why it wouldn't give me the problem if I introduced enough space between the coil and battery. After installing this lead disc between the coil and battery, the issue is resolved. Thank you again for the help!
simulate this circuit – Schematic created using CircuitLab
A basic circuit which ought to work would be as above. The diodes should be rated at least 2A - the 1N5400 is 3A. The tricky bit is going to be the resistors. If you put 5W through a 21W lamp, it will glow feebly. You would need some trial-and-error to find what actually works. The resistors need to be high power wire-wound ones.
Best Answer
It's for power. The power from the magnetic pickup is very small. It's basically a signal, not something you can run a light from directly. The 12 V and ground connections provide the power. This small signal from the magnetic pickup triggers the strobe to fire, but the strobe is power by the 12 V battery.