How high-gain differential amplifiers use feedback to perform precise analog operations.
What is an operational amplifier?
An operational amplifier, or op amp, is a high-gain differential amplifier with two inputs and an output.
It responds mainly to the difference between its non-inverting and inverting inputs. External components and negative feedback determine the useful behavior.
Why is it powerful?
With resistors, capacitors and diodes, an op amp can add, subtract, integrate, differentiate, filter, compare, regulate and condition signals.
The same basic device can serve as an audio stage, sensor interface, oscillator, voltage reference or control loop.
The ideal model
An ideal op amp has infinite open-loop gain, infinite input resistance, zero output resistance and unlimited bandwidth. Real devices have finite gain, noise, offset voltage, bias current, limited slew rate and a restricted supply range.
Negative feedback makes the circuit predictable, but stability must be checked.
History and future
Op amps began as valve and transistor circuits used in analog computers. Integrated op amps made precision analog design accessible.
Future devices will combine lower power, wider bandwidth, better sensing and digital calibration. The central lesson is that feedback turns a raw active device into a controlled function.
Ai disclosure: written with the help of AI (ChatGPT). You are encouraged to point out errors and omissions.
