Explanation:
Latches are called memory devices because they have the ability to store and retain information. They are fundamental building blocks of digital systems and are used to store and remember data in various applications.

Definition:
A latch is a sequential logic circuit that stores one bit of data. It has two stable states, a set state and a reset state, and it can retain its current state as long as power is supplied.

Working Principle:
A latch operates based on feedback from its own outputs. It uses a positive feedback loop to store and remember information. The latch has two inputs, the data input (D) and the control input (CLK). When the control input is activated (usually by a clock signal), the latch reads the data input and stores it in its internal memory. The stored value remains unchanged until the control input is activated again.

Types of Latches:
There are different types of latches, such as SR latch, D latch, JK latch, and T latch. Each type has its own specific characteristics and applications.

Storage Capacity:
Latches are called memory devices because they can store and retain one bit of data. This means they have a storage capacity of one bit. The stored bit can be either a logic 0 or a logic 1, and it remains stored until it is changed by a subsequent input.

Applications:
Latches are used in various applications where data storage and memory are required. Some common applications include:
1. Register circuits: Latches are used to store data in registers, which are used for temporary storage and data transfer in digital systems.
2. Flip-flops: Latches are used as building blocks for flip-flops, which are used for synchronization and sequential logic operations.
3. Memory elements: Latches are used as memory elements in memory units, such as RAM (Random Access Memory) and cache memory.

In conclusion, latches are called memory devices because they have the capability to store and retain one bit of data. They are widely used in digital systems for various applications that require data storage and memory.