Re: why 4 Ohms in PARALLEL with trigger coil primary?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "James T by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jamest2000-at-att-dot-net>

Hi Guys,

 I think one possible reason for the resistors is to insure a clean zero
crossing. This is essential
for cheapo single or double time constant diac/triac circuits to run
smooth. The triac also has the
nasty habit of staying "on" if the voltage across its main terminals does
not go below the "hold on"
voltage, usually 2 volts or less. All this crerates erratic operation. If
the triac is tricked into
staying on for the occasional half cycle the coil will not fire on that
half cycle. After all the
ignition coil is a pulse transformer, I doubt it would work well is given a
clean sine wave(correc t
me if I'm wrong on that).

> Original poster: "Metlicka Marc by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <mystuffs-at-orwell-dot-net>
>  i connected the
> resistor before the cap i could maintain the trigger arc, by itself,
> throughout a wider range of the dimmers adjustment.

   Makes sense. As Terry noted this is more like a resistive load the
circuit was designed for.

>  It seems like
> > >these resistors would burn right up.

 I have to agree. They should get real hot anyway. I have used a regular
light bulb with good effect,
except for the annoying extra light source, I just covered the bulb with a
theactrical gel.
James Cart