MOSFET Current Mode Resonant Coil Driver: The schematic was
made long after the circuit was built and perfected. Sorry. That
means I cannot guarantee that it is free of errors. However, the
schematic was compared to the original as best as I could.
ERRATTA: 1. The resistor network at pins 6 and 7 of the LM555 is
incorrect. Instead of a fixed 200k and a 500k pot in parallel,
it should be the 200k fixed in parallel with a 500k pot and the
resulting two in series with a 1k fixed. Thus the 200k fixed
established the maximum duty cycle, and the 1k pot establishes
the minimum duty cycle. You could try eliminating the 1K, but
you might damage the LM555.