IC OPERATIONAL AMPLIFIER
IC Operational Amplifier –
As on OP AMP is a high gain amplifier , “the difference amplifier , which was discussed earlier forms its basic building block to make it more efficient.
input → V1 and V2
V0 α ( V1 – V2 )
an IC OP AMP consists of four cascaded stage shown in fig.
1. The first stage is a difference Amplifier with a double ended output. This amplifier is provided with a constant current so and thus , it possesses a large CMRR also helps to reduce the effects of change in temperature , change in supply Vc and ageing. The input resistance of this stage is high.
2. The double ended output of the first amplifier is directly connected to the two inputs of the second amplifier state . Than achieve a very large gain and also a large CMRR.
The output is taken between the collector of any one of the transistors and the common ground.
3. The third stage is this stage therefore acts as a buffer between the second and fourth stage and thus avoids an unavoidable loading .
4. The last stage helps to bring output to zero volt level i.e to ground potential, in absence of any input in the direct coupled amplifier , the DC voltage level at the base of each succeeding stage increases with respect to ground as the signal progresses through the amplifier.