Test: Latches - GATE MCQ

When both inputs of SR latches are low, the latch remains in it’s present state. There is no change in output.

SR or Set-Reset latch is the simplest type of bistable multivibrator having two stable states. The inputs of SR latch are s and r while outputs are q and q’. It is clear from the diagram:

The NAND latch works when both inputs are 1.

SR or Set-Reset latch is the simplest type of bistable multivibrator having two stable states.
The diagram of SR latch is shown below:

There are four types of latches: SR latch, D latch, JK latch and T latch. D latch is a modified form of SR latch whereas, T latch is an advanced form of JK latch.

Latches can be memory devices, and can store one bit of data for as long as the device is powered. Once device is turned off, the memory gets refreshed.

A latch is an example of a bistable multivibrator. A Bistable multivibrator is one in which the circuit is stable in either of two states. It can be flipped from one state to the other state and vice-versa.

When both gates are identical and this is “metastable”, and the device will be in an undefined state for an indefinite period.

S input of an SR latch is directly connected to the output Q. So when a high is applied Q output goes high and Q’ low.

All flip flops have at least one output labeled Q (i.e. inverted). This is so because the flip flops have inverting gates inside them, hence in order to have both Q and Q complement available, we have atleast one output labelled.