[SML] fluoro fixtures replacing

[billn at peak.org]

> The fixture in my garage is over forty years old, and has had one new
> tube in that time. It is of an unusual design, in that there is no
> starter. It is called a "resonant start" fixture, and strikes
> immediately when powered. I do not really understand its working. I
> assume that the inductor and capacitor are resonant at our 50Hz mains
> frequency, to provide the strike voltage. Also, we have 230V to start
> with, so this may not work with 120V supplise.

I don't know much about resonant start fixtures except that they contain both
a transformer and capacitor - there is no ballast as the transformer provides
the inductance. There are also cathodes which are heated by a winding on the
transformer. The resulting LC circuit resonates at line frequency when no
current is flowing in the lamp, providing the voltage needed to start the arc
as soon as the cathodes pull the lamp striking voltage low enough.

The design works fine on 120 V power.

Bill