Contents
What are triacs and diacs?
DIAC stands for Diode AC switch. TRIAC stands for Triode AC switch. DIAC is a bidirectional device that lets current pass through it in both directions when the voltage across the terminals reaches break-over voltage.
What is the difference between TRIAC and transistor?
Uni-junction transistor is used for triggering in SCR but in TRIAC the DIAC is used for triggering. Thyristor control DC power whereas TRIAC control DC as well as AC power. A thyristor is only one mode of operation is possible while TRIAC has four different modes of operation is possible.
What is full form of Triac?
A TRIAC (triode for alternating current; also bidirectional triode thyristor or bilateral triode thyristor) is a three terminal electronic component that conducts current in either direction when triggered.
What are the different uses of diac and TRIAC?
DIAC is used to build different circuits like lamp dimmer, heat control, the universal motor speed control circuit & starter circuits used in fluorescent lamps. TRIAC is used in the control circuits such as motor control, fan speed controlling, light dimmers, switching of high-power lamps, controlling of AC power in domestic applications.
What do you need to know about opto TRIACs?
Understand a typical triac characteristics diagram. Understand the basic principles of opto triacs. Understand the operation of diacs. Understand methods and limitations for out of circuit testing of thyristors. Safety considerations for using medium and high voltage devices.
Why are TRIACs used in high voltage circuit?
This provides safe isolation between a low voltage control circuit and high voltage high current output. Although the output current of opto triacs is usually limited to tens of milliamps, they provide useful interface when the output is used to trigger a high power triac from a low voltage opto triac.
What is the break over potential for DIACs?
The break over potential for diacs is typically around 30 to 40 volts. This action makes diacs particularly useful in triggering triacs in AC control circuits because of its ability to trigger the triac during either the positive or the negative half cycle of the mains (line) waveform.