Differential amplifier
Overview
Electronic amplifier
An electronic amplifier is a device for increasing the power of a signal.It does this by taking energy from a power supply and controlling the output to match the input signal shape but with a larger amplitude...
that amplifies the difference between two voltages but does not amplify the particular voltages.
Many electronic devices use differential amplifiers internally.
The output of an ideal differential amplifier is given by:
Where
and 
are the input voltages and 
is the differential gain.In practice, however, the gain is not quite equal for the two inputs.
