Brightness display circuit 555
Posted on Nov 10, 2015 5312
As shown for the brightness display circuit. The circuit consists of light-sensitive sensor, an oscillation circuit, LED display circuit. Wherein the light-sensitive
sensor that is photosensitive resistance Rd. Of the multivibrator Rd, R1, W1, R2, C1,555 composed. The oscillation period of kitchen charge + 7 = f women. Where T charge = 0.693R2C1, t put = 0.693 (Rw1 + R1) Rd / (Rw1 + R1 + Rd) C1. Due to changes in light intensity Rd with two Ju different resistance, so that the oscillation frequency f = 1 / T is changed, the oscillation waveform duty ratio D = t charge / T also changed. When the light intensity and oscillation frequency increases, the duty ratio becomes smaller, the oscillation signal and the corresponding end (A, B, C, D) through IC2 (CD4011) after driving the corresponding light emitting diode operating, the LED brightness increases.