240 VAC-to-110 VAC converter

From time to time one comes across appliances in second-hand goods stores that were designed for operation from a 110 V a.c. (50/60 Hz) supply. If such an appliance is a pure resistive load, such as a radiant fire, a soldering iron, or a melting furnace, the circuit shown may be found useful. Strictly speaking, it is a dimmer set so that the output voltage has an r.m.s. value of 110 V. It is, of course, possible to set it to a different output voltage if so desired.