The Emitter-Coupled Differential Amplifier

The transistor emitter-coupled differential amplifier is analogous to the cathode-coupled differential amplifier and gives promise of excellent utility in transistorized circuitry. Expressions are given for 1) the circuit voltage gain, current gain, and input impedance, 2) the common-mode rejection when the circuit is used as a differencing amplifier, and 3) the signal unbalance when the circuit is employed as a single-ended-to-push-pull amplifier or phase inverter. When the circuit is used as a dc amplifier, drift generated by variations in the temperature-sensitive parameters cancels to a satisfactory degree.