Which of the following is both Latch ON and Latch OFF device Select one:a. Triac b. SCRc. GTOd. Diac

The correct answer is a. Triac.

A Triac is a three terminal (MT1, gate, and MT2) four-layer (PNPN) semiconductor device that is used in controlling AC power. The device can be turned on and off in both the forward and reverse bias conditions. This means it can conduct in both directions, making it a bidirectional device.

In contrast, an SCR (Silicon Controlled Rectifier) is a unidirectional device, meaning it can only conduct current in one direction when triggered.

A GTO (Gate Turn-Off Thyristor) is also a unidirectional device, but it can be turned off by applying a negative voltage to the gate.

A Diac is a bidirectional trigger device, but it cannot be turned off once it is triggered. It will only turn off when the voltage drops below a certain level.

Therefore, the Triac is the only device among the options that can be both latched on and off.