One last job: remember

Every circuit so far forgets immediately. Change the inputs and the output changes with them.

To keep a value, a circuit needs feedback. That means sending part of its output back as an input.

In this simplified circuit, a brief 1 turns the output on. The output travels around the loop and returns to the gate, so it keeps itself on after the first signal disappears.

Break the loop and the stored 1 disappears. The output returns to 0.

Press the input to send the 1, then press it again to break the loop. Real computer memory uses carefully controlled circuits with more parts, but feedback is the central idea: an earlier output can help preserve the current state.

One last job: remember

Every circuit so far forgets immediately. Change the inputs and the output changes with them.

To keep a value, a circuit needs feedback. That means sending part of its output back as an input.

In this simplified circuit, a brief 1 turns the output on. The output travels around the loop and returns to the gate, so it keeps itself on after the first signal disappears.

Break the loop and the stored 1 disappears. The output returns to 0.