Transistors in video equipment

Principles involved in the design of video current amplifiers for television using transistors are discussed in terms of the hybrid-pi equivalent circuit. The importance of the current gain-bandwidth factor is emphasized and a design philosophy which exploits an unconventional concept of gain-bandwidth is presented. An investigation of noise with regard to camera head amplifier design gives the transistor parameters and circuit conditions necessary for maximum signal/noise ratio. Experimental confirmation shows transistors to be comparable with valves in this application.