The Difference Amplifier-An Explanation for the Undergraduate

An elementary analysis of the difference amplifier is presented in this paper in a form that is easily understood by undergraduates. Basic operation of the amplifier, the significance of the "common-mode rejection ratio," the maximum allowable input signal level, and the use of "balancing resistors" in the emitter circui'ts are the principal topics covered. In addition, a practical difference amplifier using balancing collector-coupled transistors is analyzed.