Following are main difference between SCR (Silicon controlled rectifier)and TRIAC (Triode for alternating current) :
| SCR | TRIAC |
|---|---|
| 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