Working principle diagram of RS flip-flop

Shown is a diagram showing the working principle of the RS flip-flop. When the switch is neither at the S end nor the R end, the output end of the flip-flop

is uncertain. When the switch is set to one side, it determines the output of the flip-flop. For example, when the switch is placed at the S terminal, the S terminal is low level (ground).

The R terminal is high level, the input of NAND gate ① is low level. The input of NAND gate ② is high level. In this way, the Q terminal output of the flip-flop is

High level, the output of Q terminal is low level.

If the input switch is placed at the R terminal, the flip-flop will reverse, the Q terminal becomes low level, and the Q terminal becomes high level.

all

It can be seen that the input terminals R and S can neither be high level nor low level at the same time. There are only two situations, among which

If one is high level and the other is low level, signals with opposite status will inevitably appear at both ends of flip-flop Q and Q.