Basic Latch

A basic latch is a fundamental building block in digital electronics. It is a simple circuit that can store a single bit of information. The basic latch consists of two inverters connected in a feedback loop.

Working Principle

The latch operates based on the principle of positive feedback. When an input signal is applied to one of the inverters, it produces an inverted output. This inverted output is fed back to the input of the other inverter, causing a continuous loop.

Feedback Loop

The feedback loop in the latch ensures that the output state remains stable even after the input signal is removed. It allows the latch to "remember" the previous state until a new input signal is received.

Set and Reset

The basic latch has two inputs: set and reset. The set input is used to store a '1' or logic high state, while the reset input is used to store a '0' or logic low state.

- When the set input is activated, it drives one of the inverters to produce a logic high output. This high output propagates through the feedback loop, reinforcing the high state.
- Similarly, when the reset input is activated, it drives the other inverter to produce a logic low output. This low output propagates through the feedback loop, reinforcing the low state.

State Retention

Once the latch is set or reset, it retains its state even if the input signals are removed. This is due to the positive feedback loop that maintains the output state until a new input signal is applied.

Level-Sensitive Latch

The basic latch described above is known as a level-sensitive latch. It is sensitive to the levels of the input signals and changes its state accordingly. It is commonly used in sequential logic circuits, such as flip-flops.

Conclusion

In summary, the basic latch consists of two inverters connected in a feedback loop. It operates based on positive feedback and can store a single bit of information. The latch has set and reset inputs, which allow it to store either a logic high or logic low state. The positive feedback loop ensures that the latch retains its state until a new input signal is received.