Which of the following is both Latch ON and Latch OFF device Select one:a. Diacb. SCRc. Triac d. GTO

The correct answer is c. Triac.

A Triac is a three terminal (MT1, gate, and MT2) semiconductor device that is used for controlling current. It is a type of thyristor and can conduct current in either direction when it is triggered. Therefore, it can be used for both Latch ON and Latch OFF operations.

Here's a step by step explanation:

1. Latch ON: When a small current is applied to the gate terminal, the triac starts conducting current between its two main terminals (MT1 and MT2). This is the Latch ON operation.

2. Latch OFF: The triac stops conducting when the current flow drops below a certain level known as the holding current. This is the Latch OFF operation.

In contrast, a Diac can only conduct in one direction and an SCR (Silicon Controlled Rectifier) can only turn off when the current flow drops to zero. A GTO (Gate Turn-Off Thyristor) can be turned off by applying a negative voltage to the gate, but it is not typically used for latching operations.