P-Series Valves, what to do with them?

[Murphyv310]

Andy, thanks for doing the simulation. Any chance of doing it with a resistor whose resistance is comparable to the reactance of the cap?

I don't see how a capacitor can act as an approximation to a constant current source. Unless its reactance is substantially greater than the load resistance. If the reactance of the cap (or resistance of the dropper) is fairly large compared to the heater chain then it will indeed approach being a current source. But that isn't what's normally happening in a real life heater chain.

Quite right Jeffrey - see the attached screen-grab : It's a simulated circuit with six parallel paths having the same value capacitor but with progressively smaller load resistances.

I must admit that when I was experimenting with a dropper circuit, the capacitive reactance was much greater than the load resistance giving the apparent results I described.

Andy

Hi Andy.
The figures are just about what I get, a 4UF cap with no series resistor and 235v AC into the load that adds up to 165v gives me 309ma.
From my calcs the heater chain would be equivalent to 550 ohms when hot?