Light-controlled street light circuit using TWH8778 (1)

It is an automatic street light composed of
TWf18778 power switch integrated circuit . Its circuit working process is as follows: F: During the day, the photoresistor RP shows low resistance when exposed to natural light! The plate tube VT is turned on, and its collector outputs low level . The control terminal of TWFI8778, i.e. the fifth pin iLl, is about 0 2V. The internal power supply rr is turned off and the relay K does not act . The J lamp F does not light up: at night. RI. High voltage will appear under no light irradiation, VT is cut off, and the level of pin ⑤ of TWH8778 is determined by the ruler. The partial voltage with R is about 18V, and the large door opening level is 1W, so the electronic switch on the integrated block f^J is closed, that is, the ① pin is connected to the ② and ③ pins, the relay K draws the base, and the closing contact k is established. - 1 is closed, the circuit ¨E is energized and glows.     vs, bar and R; it forms a simple voltage stabilizing source, providing 10V stability for VT J． operating voltage, plus the absorption network R, and G, so the circuit works very reliably. RP is the light control sensitivity adjustment potentiometer. Adjusting RP can make the street lamp start to light up under the appropriate illumination .