An operational amplifier, commonly referred to as an op-amp, is a fundamental electronic component used in various analog circuits. It is a high-gain, direct-coupled amplifier with a differential input and typically a single-ended output. Op-amps are widely used in analog signal processing, amplification, filtering, and many other applications due to their versatility, high gain, and low input impedance.
The symbol for an op-amp looks like this:
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+---> Output
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GND V+ V-
Key characteristics of an ideal op-amp:
High Open-Loop Gain: An ideal op-amp has an infinite open-loop gain, which means it can amplify even tiny voltage differences at its inputs significantly.
Infinite Input Impedance: An ideal op-amp has infinite input impedance, meaning it draws no current from the sources connected to its inputs.
Zero Output Impedance: The output impedance is ideally zero, allowing it to drive loads without significant loss of signal.
Zero Offset Voltage: The voltage difference between the two inputs (V+ and V-) is zero in an ideal op-amp, but in real-world op-amps, there can be a small offset voltage.
Infinite Bandwidth: An ideal op-amp can amplify signals over an infinite range of frequencies.
Infinite Slew Rate: The slew rate represents the maximum rate of change of the output voltage. An ideal op-amp has an infinite slew rate.
In practical applications, real-world op-amps do not perfectly meet all these ideal characteristics. Manufacturers design various types of op-amps with different specifications to suit different applications.
Op-amps are typically used in feedback configurations, such as inverting amplifiers, non-inverting amplifiers, integrators, differentiators, and many other configurations to achieve specific circuit functionalities. The feedback network around the op-amp determines the overall behavior and function of the circuit.