This circuit is used for controlling volume of audio amplifier digitally. The heart of this is CD4066. In CD4066 we can find about 4 electronic switch that can be arranged in to 16 step of volume, depends on the logic combination at ABCD input. The combination is depict at table 1.

If we cannot to find 8k ohm resistor, we can to arrange 4x2kohm resistors in series manner. ABCD input can be connected to micro controller systems or up and down counter.

Figure 1. Digital Volume Control Using CD4066

Table 1. Amplification based on control combination logic

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