Difference between SCR and DIAC

The difference of SCR (silicon controlled rectifier) and DIAC (diode alternating current) are given below,

The SCR stands for silicon controlled rectifier. The DIAC stands for diode alternating current.
The SCR is a four layers PNPN device with three terminals namely anode, cathode and gate. The DIAC basically a two terminal device. It is a parallel inverse combination of semiconductor layers that permits triggering in either direction.
It is a high power device. It is low power device..
It is a three terminal device. It is a two terminal device.
The break over voltage can be controlled by adjusting the gate current. The break over voltage cannot be controlled.
The symbol is

The symbol is

The breakdown voltage is ± 26 V. The maximum anode current is 25 mA. The forward break over voltage is 40 V. The maximum anode current is 100 A.
It is used in applications like dimmer, control light, fan etc It is used as a triggering device for the TRIAC.


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