Following are main difference between SCR (Silicon controlled rectifier)and TRIAC (Triode for alternating current) :
|SCR stands for silicon controlled rectifier.
||TRIAC stands for triode for alternating current.
|The SCR is unidirectional device.
||The TRIAC is bidirectional device.
|It available in large ratings.
||It available in smaller ratings.
|The SCR control DC power.
||The TRIAC control DC as well as AC power.
|The SCR can be triggered by positive gate voltage only.
||The TRIAC can be triggered either by positive or negative gate voltage.
|In SCR only one mode of operation is possible.
||In TRIAC four different modes of operation is possible.
|It is more reliable.
||It is less reliable.
|The SCR conduct current in one direction only.
||The TRIAC conduct current in both the directions.
|It needs two heat sink.
||It needs only one heat sink.
SCR Vs TRIAC