1. What is Differential Gain?

Differential gain is a measure of the amplification of the difference between two input signals in a differential amplifier. It's a key parameter in operational amplifiers and other differential circuits.

2. How Does the Calculator Work?

The calculator uses the differential gain formula:

Where:

• \( R_f \) — Feedback resistance (ohms)
• \( R_e \) — Emitter resistance (ohms)

Explanation: The formula shows that differential gain is directly proportional to the feedback resistance and inversely proportional to the emitter resistance.

3. Importance of Differential Gain

Details: Differential gain is crucial in designing differential amplifiers, instrumentation amplifiers, and other circuits where signal differences need to be amplified while rejecting common-mode signals.

4. Using the Calculator

Tips: Enter both resistances in ohms. The values must be positive numbers. The result is a unitless gain factor.

5. Frequently Asked Questions (FAQ)

Q1: What's the typical range for differential gain?
A: In practical circuits, differential gain typically ranges from 1 to 1000 or more, depending on the application.

Q2: How does differential gain relate to common-mode gain?
A: The ratio of differential gain to common-mode gain is called the Common-Mode Rejection Ratio (CMRR), an important specification for differential amplifiers.

Q3: What happens if Re is zero?
A: The formula predicts infinite gain, but in practice, other factors limit the gain and very small Re values can lead to instability.

Q4: Can this formula be used for all differential amplifiers?
A: This formula applies to basic differential amplifier configurations. More complex circuits may require different calculations.

Q5: How does temperature affect differential gain?
A: Temperature changes can affect resistor values and transistor characteristics, potentially altering the actual differential gain.