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Sparkplug Coils to Replace the Neon Sign Transformer..




    I was doing some calculations to determin the equivalent of a neon sign
transformer, and the closest I could get without over heating being a
problem in the transformer was a Parallel circuit using four sparkplug coils
running in the range of 298.4 Hz to 497.3 Hz.  I was using the frequency to
control the current of the input, and limit it to the wire gauge's current
handling limit in the transfomer.  So, the 22 AWG can handle an ampere of
current in a circuit, but because of the resistance of the length of wire,
and it's inductance it's actully limited to 640.1 mA on the primary.  So, if
it doesn't equal 18.747 ohms it's to high.  Based on a 1 : 100 turns ratio
has a stable output of 25 mA, which is pretty close to a Neon sign
transformer's output of 30 mA.

    The circuit that I am designing to run this uses a 555 NE timer for a
square wave output to control a pulse width trigger that I can adjust the
timing cycle to 50% with.  So, every time I adjust the frequency knob, I
will need to adjust the symetry knob, or I'll just use a op amp oscillator
to drive a group of MOSFETs.  I don't know how many I'll be using yet,
because heat it is the issue here.