Light-operated potentiometer circuit composed of phototransistor

Published:2012/8/19 22:58:00 Author:Ecco | Keyword: Light-operated, potentiometer , phototransistor | From:SeekIC

Light-operated potentiometer shown as the figure uses the laser pointer for light source to reflect light to photodiode VT1, then the channel resistance reduces, the volume increases; if the irradiation on VT2 reduces, the volume declines, therefore to achieve light-operated volume adjust. Every time you turning on the potentiometer, the VT3 tube's G potential is 0V, the channel resistance is in the maximum value, the volume will be kept the minimum value. The figure shows a mono, if you need to control multiple channels, you only need to connect FET G pole in parallel. The VT3 selects 3DJ6F or similar FET. VT1, VT2 is available to use commercial NPN photodiodes, C1, , C2 , C3 use 6.3μF/25V tantalum electrolytic capacitors. Resistor selects 1/8W metal film resistor.



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