7- Differential Amplifiers: Small-Signal Analysis

DIFFERENTIAL AMPLIFIER: A differential amplifier built using two NPN BJTs. It is powered by a dual ±20 V supply and uses matched resistors for symmetry. The circuit amplifies the difference between two input signals—one at 1 kHz and the other at 2 kHz—while rejecting any common-mode signals. The shared emitter resistor (100 Ω) provides negative feedback, improving linearity and stability. Differential amplifiers like this are commonly used in analog signal processing @and the input stages of op-