SHEILA TERRY / SCIENCE PHOTO LIBRARY SHEILA TERRY / SCIENCE PHOTO LIBRARY
Interior of a domestic light dimmer switch. The black component with the perforated metal panel is the central element of the switching circuit of the dimmer. It is a small semiconductor device known as a triac â a triode alternating current switch. This is a bidirectional triode thyristor which has a similar function as the variable resistors of earlier types of dimmers but is much more efficient and produces less heat, thus saving energy. The metal panel acts as a heat sink. The triac switches the light circuit on and off 100 times per second (in Europe) reducing the amount of energy used.
Model release not required. Property release not required.