Gated automatic light circuit (3)

The door-controlled automatic light is cleverly made using an ordinary clock chip. It has the following
main functions: ① When I go home at night and open the door, the light can automatically light up for about 20 seconds, eliminating the need to search for the light in the dark. Trouble
; ② If it is not automatically locked during the day, the light will not light up when the door is opened; ③ The wiring is simple and you can directly connect
the two ends of any light that is turned on in parallel. This light has door control and light control functions.
    In the figure, the dotted
line is the general
lighting circuit, and the left
part is the automatic switch
part. When switch S is closed
, lamp E
lights up just like an ordinary switch
. When S is turned on
, the turning on and off of the electric light E
is controlled by the door support and light control. VIl - VD4 and VT3 form the main circuit of the white light switch VT1,
VT2 and KD-9:/C. 『The bell chip forms the control circuit of the switch. K is the reed switch in the door and window sensor, which is
installed on the f J frame, and the small magnet in the sensor is installed on the door. Dangmengo III}． The magnet is exactly aligned with the ten-reed
tube, so that its contacts are magnetized and attracted, VII is in the cut-off state, KD-i300 is in a static state without a trigger signal,
WI2 cuts IL, gate tube VI 3 is turned off, and the light E lights up.
    Open the door and move the magnet away from the lower reed. Its connected electric jumper VT1 is forward-biased by RI' and conducts. The trigger
terminal TRIG of KD9300 is triggered by the high electric current, and its output terminal L), P outputs a sound of about 20 seconds. The music signal,
VT2 is turned on, so there is a positive trigger current flowing through the gate of the transistor VT3 to make it closed, so the lamp F lights
up and shines when the music ends. VT2 resumes cutoff, VTS is turned off, and the light E goes out. The function of R, and G
is enough to smooth the music number of VT2 input III, which can eliminate the flickering of light brightness with the rhythm of music. The bright time of this circuit
is determined by the length of music stored in the Zhanle doorbell chip. Since the consumption of the music integrated block is very small,
when VT3 is in the open state, although the voltage at both ends of VT3 drops (amplitude), There is still a DC
voltage of about 2V, which can still ensure the normal operation of the music integrated block until the previous music output is completed.
    The photoresistor RI. 5 RP forms a light-pressing circuit. During the day, RG is low resistance, and the K
contact When the drawer is closed or jumps up, the voltage of VT1 is always low, and VT1 can only be in the cut-off state, so it may
cause the downstream circuit to work. Unless switch S is closed, the lamp E can be lit. When used at night , when the door is opened and
closed, K is closed and the light is on, bright light shines on RI, making it show low resistance. These factors
will cause VT1 to enter the intersection. But because After the music integrated block is triggered, if the trigger signal disappears, it can still
output the complete music signal, so VT1 cuts off immediately and will not affect the length of time the light is on. RI,
to adjust the light sensitivity, requires that it be during the day Under natural light indoors, VT1 can be blocked so that it is always in
a cut-off state.