Discrete component sound and light control stair delay switch circuit (5)

A light-controlled stairway delay lighting switch with a relatively simple circuit. The shortcoming is that the voice control
sensitivity is slightly lower, and it is sometimes difficult to trigger it with normal conversation. However, it can be activated by tapping the F sound on the shoulder or directly tapping
the switch panel. lamp.
    Photoresistor Rl. ,
R, and VT2 form a light control
lb circuit, H day, RI. It shows
low resistance, VT2 is turned on,
VT3 door panel is clamped at
low level, VT3 is turned off, and
the light E does not light up. At this time
(jlⅡ is powered to about 13 (iV) through VDa and Suike
(vs the regulated voltage value plus the positive voltage drop of the light-emitting tube LED). At night, RI is high resistance,
VT? is cut off, and the blockade of VT3 is released, but due to R,.i is far away from DingR, VT3 is still in the off state, and the light is still
off. When someone talks or claps or claps, Ij picks up the sound wave signal through (.coupling, and directly triggers VT1 to turn on
, at this time 1: ~. The power supply of about 6V passes through VD6 and VT1 to the VT3 f J pole, causing VT3 to trigger and turn on, and
the lamp E is powered on and emits light. After the sound, VT1 loses the f J pole}U current, but is connected to C, and the stored charge passes through R. Put In to
VT1, so that VT1 works under the positive claw, so VT1 can still remain open. (jhui
: while discharging, it is also affected by VDj, R, full-wave pulsating DC charging but R; large stem R, , so (1. The voltage at both ends
gradually drops, and Sheng eventually cannot maintain VT1 on. When the pulsating DC crosses zero, VT1 turns off. At this time, C.
continues to charge through VDo, R, and the VT3 gate, and its charging The current can keep VT3 in the on state until
f is fully charged, and V[3 loses its master and triggers the current. When the alternating current crosses zero, it is turned off and the lamp E goes out.
    The luminous tube I.EI) collapses at this time: one foot at night It emits weak light to indicate the switch position; secondly, it plays an isolation
role so that the VT] anode and VT3 gate usually work under the full pulsating DC voltage condition F. The fine-tuning resistor
RI' is used for the sound control sensitivity of the side section circuit. Increase the sound control sensitivity of the side section circuit. Decreasing the resistance value of resistor R. can adjust the light control starting
point of the circuit; after the circuit is powered on, if the light F stays on, you can increase R. (or decrease the wind) for adjustment.