voltage- controlled audio switch - switches sounds electronically

switches sounds electronically In a few situations it is desirable to be able to switch audio signals elec- tronically. One such situation is the muting circuit in FM receivers that substitutes silence for annoying noise when there is a very weak, or no, carrier signal present. This is the sort of switching function that electronic switch ICs, such as the 4016 or 4066, revel in. The circuit shown here works on a symmetrical ± 7.5 V supply but the IC containing the switches simply has +15 V. This set-up allows the circuit to work with pure a.c. signals. The operation of the circuit is quite straightforward. If the control input (x) is at +7.5 V ES1 will be closed and ES2 open. The effect is then that of an inverting unity gain amplifier. If, on the other hand, x is at —7.5 V ES1 opens and ES2 ES1 R2 5k I---. Al ES1,ES2 = IC1 = 4066 A1 =Y