Common-Emitter Transistor Video Amplifiers

A design procedure and theory are given for the common-emitter transistor video amplifier with and without a feedback resistor in the emitter lead. In the analysis a junction transistor of the alloy type is represented by the Johnson-Giacoletto hybrid-pi equivalent circuit for the common-emitter transistor. The design theory accounts for the most significant part of the bilateralness of the transistor by adding a "Miller" capacitance term to the diffusion capacitance of the common-emitter transistor. Gain-bandwidth products and optimum load resistors determined for a cascade of amplifier stages are reported. The figure of merit of the transistor in a cascade of identical video amplifier stages is compared with the figure of merit of a transistor used as a power amplifier. The theory and design are given for the process of obtaining a maximally flat frequency response in a single stage by means of a capacitor shunting the feedback resistor, or by means of inductances in the amplifier interstages. Experimental results for the capacitor compensation scheme are given.