To achieve silence at zero volume with LDR's , you need to use just one gang of a 50k potentiometer, arrange the series pairs as Volume Up and Shunt pairs as Volume Down and have the wiper as the lower potential, but not directly grounded.
You then need a current source/sink , as it is a bit ambiguous, as to the nature of which, in this circuit. Some will say it has to be one or the other, but an understanding of the overall circuit will show it is both depending on the positioning of the potentiometer.
Arranged with a LM317 have the series pair cathodes at Vin of the LM317, and Adj with a resistor leading out to a higher voltage source, its value has relationship to anode voltage, so can take some discovery as all other circuit values relate ... 24k is a good value to begin with, where anode voltage is 10v
The start resistor then connects to always a higher voltage than the LDR anode voltage typically at least 2.5v higher than series anode voltage.
As the main 50k potentiometer moves toward the shunt pairs away from the series pairs, it reaches a point where the series pairs cathodes then exhibit very high, and at zero volume extremely high resistance, well beyond the manufacturers data for a NSL32SR3 Typical measurements for resistance are beyond the 200mega ohm capability of my Fluke multimeter. End result is perfect silence at zero volume , with also volume commencing where chosen.
The diagram shows a variable edition to more easily discover the needed start volume position.
I hope this helps you.
You then need a current source/sink , as it is a bit ambiguous, as to the nature of which, in this circuit. Some will say it has to be one or the other, but an understanding of the overall circuit will show it is both depending on the positioning of the potentiometer.
Arranged with a LM317 have the series pair cathodes at Vin of the LM317, and Adj with a resistor leading out to a higher voltage source, its value has relationship to anode voltage, so can take some discovery as all other circuit values relate ... 24k is a good value to begin with, where anode voltage is 10v
The start resistor then connects to always a higher voltage than the LDR anode voltage typically at least 2.5v higher than series anode voltage.
As the main 50k potentiometer moves toward the shunt pairs away from the series pairs, it reaches a point where the series pairs cathodes then exhibit very high, and at zero volume extremely high resistance, well beyond the manufacturers data for a NSL32SR3 Typical measurements for resistance are beyond the 200mega ohm capability of my Fluke multimeter. End result is perfect silence at zero volume , with also volume commencing where chosen.
The diagram shows a variable edition to more easily discover the needed start volume position.
I hope this helps you.
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