P-N-Π-N Triode Switching Applications

The characteristics and switching applications of a developmental diffused silicon p-n-π-n triode are discussed. Although this unit is at present in a two-watt package, it is capable of handling short pulses of current of the order of 100 amperes. The electrical characteristics which consist of a low and high conductivity region (over 500 megohms and less than 1 ohm respectively), with an intermediate negative resistance region, are controllable by the base lead, and hence make it a flexible device for applications in the computer and communications fields. The theoretical and practical limitations are discussed. Experimental data covering current handling capabilities, frequency limitations and switching times are presented in conjunction with representative circuits. Two particular circuits discussed are an 80-ampere 500-mμsec pulse generator with rise and fall times in the order of 150 mμsec and 300 mμsec respectively, that can operate up to a kilocycle repetition rate, and a 4-ampere 60-mμsec pulse generator with a PRF of 100 kc. Other examples described include monostable, bistable, and astable circuits, as well as types of communication circuitry for a wide range of currents.