Calculate operational amplifier (op-amp) gain for different configurations. Essential for analog circuit design, audio amplification, and instrumentation.
Last updated: March 2026 | By Patchworkr Team
Configuration Info
Inverts and amplifies input signal. Phase shift: -180°
An operational amplifier (op-amp) is a high-gain, voltage-controlled voltage source with very high input impedance and low output impedance. It compares two input voltages and amplifies their difference. The basic symbol shows two inputs: the non-inverting input (+) and the inverting input (−).
Op-amps are one of the most important components in analog electronics. A single IC (integrated circuit) package can contain multiple op-amps with characteristics nearly ideal for linear instrumentation. Common op-amps include the TL072, NE5532, LM741, and OPA2134. They are used in audio amplifiers, audio mixing consoles, comparators, filters, oscillators, integrators, and virtually every analog electronic device.
The gain of an op-amp depends on its configuration and feedback network. The open-loop gain of raw op-amps is extremely high (100,000 to 1,000,000×), but feedback networks set the closed-loop gain to practical values suitable for applications. Understanding gain calculations is crucial for circuit design.
Voltage gain in decibels uses the formula: Gain (dB) = 20 × log₁₀(Gain)
Design an inverting amplifier with gain of -100×:
An ideal op-amp has infinite input impedance, zero output impedance, and infinite gain. Real op-amps approximate this behavior, making them practical for circuit design.
Feedback sets the gain to predictable values. Negative feedback reduces distortion, improves stability, and makes op-amp circuits practical for real applications.
Open-loop gain is the raw op-amp gain (very high, often 1,000,000+). Closed-loop gain is set by feedback resistors and is practical for applications.
Yes! Negative gain represents phase inversion. In inverting amplifiers, negative gain flips the signal 180°, which is useful in summing amplifiers and active filters.
Input impedance is the resistance an op-amp presents to the input source. High input impedance (ideal: infinite) means minimal current draw from the source signal.
Inverting has lower input impedance. Non-inverting has higher input impedance. Choose based on your source impedance and application requirements.
Frequency response describes how gain changes with frequency. Most op-amps have reduced gain at high frequencies, requiring compensation for stable operation.
Yes! Multiple stages can be cascaded. Total gain = Gain1 × Gain2 × Gain3. However, each stage adds noise and reduces bandwidth.
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