Light, sound and touch three-control stair delay switch circuit

It is a sound, light and touch controlled stairway delay lighting circuit. It makes full use
of an undeveloped NAND gate in the circuit of Example 163 , turning the circuit from the original sound and light control into a Lu, Light
and touch control.
    In the figure, the /NOT gate IV, VDb, R, and R are the newly added parts, which constitute the touch control. In this circuit
, the voice-controlled lamp is controlled by light control. See Example 163 for its working process. Touching to turn on the light is not controlled by the light control.
You can touch to turn on the light anytime day or night. When a human hand touches M, the human body leakage current flows through R. .R.
The voltage divider causes the V input terminal of the NAND gate to suddenly change to a high level, and after inversion, the output becomes a low level, and VD6 is turned on. (,; that is,
quickly charged by VD6 and NAND gate IV. When "_", the output of NAND gate III is high, the gate tube VT is opened, and the lamp F
is powered on and glows. After the finger leaves M, gate IV is reset and VD6 is cut off. .c. Through R. discharge, the gate
III output can still be maintained at a high level, so the lamps F and y5 can be illuminated externally. Until C. is basically discharged, the lU circuit is reset and the lamp E
goes out.