555 Brightness display circuit

Published:2011/7/21 3:09:00 Author:Ecco | Keyword: 555 , Brightness, display | From:SeekIC

As shown in Figure 7-32, brightness display circuit includes light sensor, the oscillation circuit and diode display circuit. Photoresistor RG is used as a shunt resistor in 555 oscillator charging loop, with the changing of background light intensity, it shows different resistance, thus affecting the oscillation frequency and the duty cycle of oscillation waveform. When the light intensity increases, the oscillation frequency increases, and the duty cycle reduces, the brightness of light-emitting diode LED increases.



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