Dial Lamp Puzzle.

[pwdrive]

For diode dropper calc, Vout = Vin x .707 then use this product to calculate the value of any additional series resistance required

Actually, Lawrence that is not quite right;

Dropper Resistance = (Vs - (Vh x 1.414)) divided by (Ih x 1.414)

where;

Vs = supply voltage
Vh = heater voltage
Ih = heater current

Regards

Hi Robert, I always thought that the diode delivers half power therefore the voltage
Vout must be .707 of Vin, that was the basis of my last post, ie: 240 volts in 170 volts out, so R = 170 minus Vh divided by Ih (at 240v mains) dissipation being the usual I sqrd R, I think it basically amounts to the same thing.

Lawrence.