Questions relating to the construction and applications of operational amplifiers, which are DC-coupled, high-gain electronic voltage amplifiers with a differential input and, usually, a single-ended output.
An operational amplifier is a DC-coupled, high-gain electronic voltage amplifier with a differential input and, usually, a single-ended output.
An op-amp produces an output potential that is typically hundreds of thousands of times larger than the potential difference between its input terminals. Operational amplifiers had their origins in analog computers, where they were used to perform mathematical operations in many linear, non-linear, and frequency-dependent circuits.
The popularity of the op-amp as a building block in analog circuits is due to its versatility. By using negative feedback, the characteristics of an op-amp circuit, its gain, input and output impedance, bandwidth, etc. are determined by external components and have little dependence on temperature coefficients or engineering tolerances in the op-amp itself.
(Excerpted from Wikipedia)
Further reading
Texas Instruments application report SLOA011: Understanding operational amplifier specifications
