An operational amplifier, commonly known as an op-amp, is a type of electronic component used in analog circuits to amplify voltage signals. Op-amps are widely used in various applications due to their versatile and reliable performance. They are designed to have high input impedance, low output impedance, and a very large open-loop gain. The open-loop gain is the amplification factor when there is no feedback applied to the op-amp.
The ideal op-amp has the following characteristics:
Infinite open-loop gain: The ideal op-amp has an extremely high gain, typically exceeding 100,000.
Infinite input impedance: The input impedance of an op-amp is extremely high, which means that it draws very little current from the source providing the input signal.
Zero output impedance: The output impedance of an op-amp is negligible, allowing it to drive loads with very little signal degradation.
Infinite bandwidth: The ideal op-amp has an infinite bandwidth, meaning it can amplify signals across a wide range of frequencies without any loss.
In practice, real op-amps have limitations and are not truly ideal but come close enough for most practical applications.
Applications of operational amplifiers:
Signal amplification: Op-amps are extensively used for amplifying weak signals coming from sensors, microphones, or other low-level sources. The amplification allows these signals to be processed further with better signal-to-noise ratio and accuracy.
Filter circuits: Op-amps are utilized in filter designs, such as low-pass, high-pass, band-pass, and band-reject filters. These filters are employed to modify the frequency response of a circuit, blocking or passing specific frequency ranges as needed.
Voltage follower: An op-amp configured as a voltage follower has its output directly connected to its inverting input. This configuration results in a unity gain buffer, used to isolate and impedance-match signal sources from loads.
Comparator: Op-amps can be used as voltage comparators to compare two input voltages and produce a digital output based on their relative magnitudes.
Oscillators: Op-amps are employed in oscillator circuits to generate periodic waveforms, such as square waves, sine waves, and triangle waves.
Instrumentation amplifier: These specialized op-amp circuits are used to amplify small differential signals in the presence of high common-mode noise, commonly found in sensor and measurement applications.
Active rectifiers and peak detectors: Op-amps are used to implement active rectifiers and peak detectors to convert alternating current (AC) signals to direct current (DC) and capture peak values of signals, respectively.
Integrators and differentiators: Op-amps can be configured as integrators (output is proportional to the time integral of the input) and differentiators (output is proportional to the time derivative of the input) in various applications, such as signal processing.
These are just some of the many applications of operational amplifiers. Due to their versatility and ease of use, op-amps find extensive use in electronic circuit design across numerous industries and applications.