Thread: Exotic Triacs

Modem power control systems use electronic devices like thyristors for power
switching, phase control, chopper, etc. These devices also find applications in inverter design, brilliance control in lamps, speed control of motors, etc. 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 levels.

Thyristors belong to a group of components known as silicon-controlled switches (SCS) or silicon-controlled rectifiers (SCR). As the name implies, their main function is to turn on/ off a current. As in diodes, current flow in odem power control systems use electronic devices like thyristors for power switching, phase control, chopper, etc. These devices also find applications in inverter design, brilliance control in lamps, speed control of motors, etc. 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 levels.



Thyristors belong to a group of components known as silicon-controlled switches (SCS) or silicon-controlled rectifiers (SCR). As the name implies, their main function is to turn on/ off a current. As in diodes, current flow in thyristors is only in one direction. The symbol of thyristor indicates that it is a diode-like device allowing current flow from the anode to cathode. A third terminal called' gate' controls the flow of current in the device.

The thyristor family includes SCRs, diacs, triacs and more exotic members like quadracs, alternistors, opto-triacs and MOS thyristors. Majority of these devices can handle high current but only a small current (a few micro-amperes) is needed to switch on the device. Instant switching action ma1;es thyristors a suitable alternative to mechanical relays in power control circuits. SCRs and triacs are the main solidstate devices used in medium-and high-voltage applications.