What is a Feedback Amplifier?
A feedback amplifier is an electronic circuit where a fraction of the output signal is fed back to the input. This technique is fundamental in modern electronics, particularly in operational amplifiers (Op-Amps) and audio systems. By introducing negative feedback, engineers can trade off total gain for improved stability, wider bandwidth, and reduced distortion. This Feedback Amplifier Calculator Online helps you quickly determine how these parameters interact without performing complex manual algebra.
How to Use the Feedback Amplifier Calculator
To use this tool, follow these simple steps: 1. Enter the Open-Loop Gain (A): This is the gain of the amplifier without any feedback applied. 2. Enter the Feedback Factor (β): This is the ratio of the feedback signal to the output signal (usually a value between 0 and 1). 3. Click "Calculate" to see the closed-loop gain, the desensitivity factor (which indicates how much the gain is stabilized), and the feedback expressed in decibels (dB).
The Core Formulas
The mathematical foundation of this calculator relies on the standard feedback equation: Af = A / (1 + Aβ). Here, "A" represents the gain of the internal amplifier, while "β" is the feedback attenuation. The term "(1 + Aβ)" is known as the desensitivity factor or the amount of feedback. As Aβ increases, the closed-loop gain becomes almost entirely dependent on the feedback network components rather than the internal amplifier itself, making the circuit highly predictable and stable against temperature variations or component aging.
Frequently Asked Questions
Why use negative feedback? Negative feedback reduces the gain but provides significant benefits such as increased input impedance, decreased output impedance, and a much flatter frequency response. It essentially forces the amplifier to follow the input signal more accurately.
What is Loop Gain? Loop gain is the product of the open-loop gain (A) and the feedback factor (β). It is a critical parameter for determining the stability and performance limits of the feedback system.