Non-two-wire sound and light control stair delay switch circuit (1)

The sound and light control stair delay lighting switch adopts a two-wire connection method, that is,
there are two lead wires for the switch and the external instrument, so the installation is very convenient. Below we will introduce some examples of sound and light control delay lights that are not connected in a one-line system.
Although the installation is more troublesome, they seem to be reliable and very
useful . Figures 1, 6 and 9 are among them. An example of.
    This circuit uses transformer T to step down, vr) 4 ~ vr) 7 bridge rectifier, f, filter output H1 about 12V L as voltage
for the whole machine. VT1 forms the preamplifier of the tongue H, RI. is a photoresistor. During the day, it shows low
resistance, bypasses the microphone signal , and clamps the VT1 base at a low level. The post-stage circuit cannot work, K does not
operate, and the light E is dimly lit. At night, RL presents a high-voltage horn, thereby lifting the blockade of VT1. If
someone L steps up the stairs at this time, B picks up the person's footsteps and converts them into corresponding electrical signals. The output is first
amplified by the front bone of VT1, and then sent to the I.M386 power amplifier integrated circuit for further amplification. After amplification, the signal passes through (1.
Input II{, VDI, VD2 double voltage rectification is converted into commercial flow control level, charges to c., and makes VD2, VT; /
conductive, K absorbs the platform, and its moving platform touches Point kl is closed, and the lamp F is energized and glows. After the person walks away, I and M386 have no
signal output. At this time ('. The stored charge can be discharged through R. to the VT2 and VT3 emission junctions, continuing to maintain their conduction
, blind to ( The charge is basically discharged in 1s. VT2 and VT3 return to cutoff, K is released, and the light E goes out. The side section
RIJ can adjust the sound sensitivity of the circuit and change the R, and the numerical value can adjust the delay time of the circuit.
The data is It can be about 20 seconds.
    It is best to use JL fine-tuning IU resistors for RP. VD1 and VD2 should use Sichuan 1X160 and 2AP9 type
germanium diodes. K port J should use JZC 22F, DC12V small and medium power electromagnetic relays. I. Use 220v, 12V,
aVA Xiaoli high-quality power supply converter, and other components are required.