dual power supply in op- amps.

[akkrz]

why we use dual power supply in op amps ??? :roll:

 

[ckshivaram]

The most common pinouts for 8 and 14 pin dips are shown to the left for quad (14-pin) and dual (8-pin) op-amps. As is the usual case each op-amp has two inputs (labeled + in, - in) and an output (labeled out). The two remaining pins on each DIP supply the power (V+ and V-). Note that there is no ground pin provided in OPAMP. Each op-amp creates its own internal (aka "virtual") ground. Most linear op-amp circuits of the kind that we use to process electrophysiological signals expect the ground to be centered between the power supply rails. Thus, we must use a bipolar supply to power most of our op-amp circuits

 

[KerimF]

For example, it helps eliminating coupling capacitors for AC signals. Their ground in between (Vcc+ and Vcc-) could be made as the reference node for both AC and DC voltages