Touch type interlock electronic switch circuit

The working principle is shown in the figure below. 74LS374 has a feature, that is, it can latch the D terminal state to the Q terminal at the rising edge of CLK (from 0 to 1); and the input high resistance characteristic of the CD4069 inverter is used to realize touch operation. Normally, the RC at the input end of the inverter causes the output end to be 0. When the i-th input is touched (i=0, 1...7), the signals induced by the human body are transmitted to the Di end and CLK end of the 74LS374 respectively through the inverter: At this time, Di=1, so that the CLK terminal has a rising edge condition, so the state of the D terminal (except Di=1, the rest are 0) is latched to the Q terminal (Qi=Di=1), and the corresponding LED lights; when the signal If it disappears (meaning it is no longer touched), it will remain in its original state because there is no rising edge condition on the CLK end. Therefore, only one light will light up when touching, achieving the purpose of reliable interlocking and indicating electronic switch.