- on Audio/Video/Photography
- Published in issue 7/2001 on page 0
Switching Amplifier for Analogue Signals
If analogue signals have to be switched, a bilateral switch such as the 4066 is often utilised. Because this IC can be powered from single-ended supply only, all the associated components are usually connected to the same asymmetrical supply (typically 8 V). The disadvantage of this is that the opamp runs on only half the power supply voltage, with the corresponding reduction in output voltage. The result is, among other things, a reduced signal to noise ratio.The circuit described here solves this problem. The design is based on the fact that the current in the bilateral switch (IC1) at zero volts can flow in both directions.