Triacs are the most common semiconductor devices used in power control and switching applications. The electronic power control circuits are designed to control the distribution or levels of AC or DC power sources. Such power control circuits can be used to manually switch power to electrical devices or to switch power automatically when parameters such as temperature or light intensities go beyond preset level. Triacs are borne with some inherent drawbacks, which will reflect in their working.
Rate effect is the unwanted effect on triac controlled circuits caused by the transients in the AC line which causes erratic functioning of the circuit. Backlash Effect is seen in Lamp dimmer circuits using triac and sometimes the lamp never turns on when the control pot is turned fully. Here are the tricks to solve both the problems.