Delay light circuit using digital circuit (3)

It is a delay light circuit for banquets and is very suitable for use on a bedside table. Its characteristic is that
if you press the button SB once, the light will turn on; if you press it again, the light will go off; if you do not press SB after the light turns on, the circuit will delay for a
period of time . The light will automatically go out; if you connect the switch again after the light goes out , it will light up again. Having this
delay lamp can make your life more convenient and add interest.
    In the figure, inverter [, Ⅱ, R-, R,,' and SB form a bistable trigger switch. Every time
SB is pressed, the level of the input H{ terminal of inverter Ⅱ changes once. R. , C, VD1 and inverters III, IV form
a monostable delay circuit, adjust column R. Or (1: The value can change the delay time of the circuit. Inverters V and VI
are used in parallel to increase its driving capability. A diode VT1 and a peripheral resistor form a thyristor VTH zero-crossing trigger
circuit. 220V AC mains power resistor R. Step-down, diode VD4, VD5 rectifier, vs voltage regulator outputs a stable
6V DC voltage for the entire circuit.
    VT1 should use 901 type 3 and other silicon NPN transistors, p≥]∞. VTH can use M/C9.1A4 type Plastic -encapsulated
bidirectional silicon. SB is a small tact switch . There are no special requirements for other components. The delay time of this circuit
can theoretically be obtained by the formula T=O. 693RsC, but due to the electrical factor of G, This will increase the delay time
to 30-SOmin, etc.