Simple light-controlled street light circuit (6)

This example introduces a simple light-controlled street light circuit with good performance , which can be used for
automatic control . The controlled road lamp can be a white bulb or an energy-saving fluorescent lamp. The circuit is shown in Figure 196. After
    the 220V DC is stepped down by the transformer T, rectified by VDl - Vl)i, and stabilized by the 7812= terminal voltage stabilizing integrated block
, a stable 12V DC voltage is output for the entire machine to power the entire machine, ensuring the control accuracy of the circuit. RL is the photoresistor
, the resistance shown during the day, VT1 is saturated and turned on, VT2 is cut off, VT3 is turned on, VT4 is cut off, the relay
K does not act, and the street light E does not light up when night falls. The resistance of RI begins to increase, causing VTl to cut off,
wr2 to conduct, and VI and 3 to cut off. VT4 is turned on, K gets electricity and absorbs f}, its moving and closing electric shock kl is closed, and the street lamp E lights
up.
    R. ,f. Forming an instantaneous light absorption loop, it absorbs the interference caused by unexpected light such as lightning to the circuit
. RPI uses meters to adjust the street lights to light up and turn off under suitable light. RP2 is used to adjust the charge and discharge
time constants of the capacitor (j). Unexpected light such as lightning and lightning will be absorbed twice, completely eliminating its influence, and it can also solve the problem. Frequent beating of the relay may occur at
the critical point of light.
    RI'1 and RP2 use WSW organic solid core trimming resistors, and RTX-1, 8w
carbon film resistors can be used for rigid fixed resistors. T is 220V/iOv , SVA small high-quality power transformer, which requires long-term power supply/heating
. K can use JZC-22F, DL12V small plow medium power electromagnetic relay, its contact capacity is iiA and 7A l
, which can be selected according to the power capacity of the controlled hoof lamp If you want to drive a sufficient number of street lights, you can use the contact
kI of relay K to control the AL: 220V intermediate relay (such as J'rx type) to solve the automatic control of all street lights in the entire community.