Simplest Ignition Coil Primary Circuit

Basic circuit to understand the flyback (back EMF) in the inductor. Use energy equation to get "C" of condenser. Target voltage 200V in primary so we get 20,000V in secondary ( secondary not shown ) As in my other circuit you need to adjust sim speed to calibrate. 1. Close switch to build max magnetic field V at inductor = 0 1s/s sim speed. 2. Pause simulation, dial down sim speed to 5us/s ( transients happen very quickly, easy to make computational errors) 3. Open switch and curve should bottom out at -200V Closest I can get is -191V for 720nF at 5 us/s 4. This voltage is stepped up in the secondary coil inside the ignition coil to a "theoretical 20kV" I figure the numbers are getting so small it's hard for my phone to calculate with no error.

published 5 years ago