Touch-type delay circuit using digital circuits (1)

It is a touch delay lamp made of CD4013 digital integrated circuit. The power supply of this circuit
is step-down by C, rectifier by VD2 and voltage stabilization by vs. After power on, [1: Both ends can output a stable DC voltage of 12V for
the entire switch. .
    CD4013 is a D flip-
flop. The circuit only uses
one D flip-flop and connects it
into a typical monostable circuit.
When the input voltage is stable, terminal Q, that is,
pin ①, outputs low level , diode
VT1 is cut off, thyristor
VTH has no trigger current and is in
the off state, and the lamp E does not
light up. If someone touches the electrode
M, the stray signal from the human body passes through the resistor R. Added to the (CP terminal of the integrated block is the ③ pin, the monostable circuit flips into
a transient state, and the Q terminal, which is the ① pin, outputs a high level. This high level passes through the resistor R. VT1 is turned on, and the thyristor
VTH passes through VT1 and R. The trigger current is obtained and quickly turned on, the lamp E is turned on, and the LED of the light-emitting tube
lights up for indication. The other path passes through R and charges Cz, so that the level of the reset terminal R of the integrated block, that is, the ④ pin, continues to rise.
When When it rises to the threshold level , the circuit resets, the monostable circuit returns to the stable state, pin ① returns to the original low level, VT1 is cut off, VTHⅢ loses the trigger current, and when the alternating current crosses zero, it turns off and /E goes out.