Nonsaturating Transistor Circuitry for Nanosecond Pulses

A system is described for pulse testing of transistors in the 10-10 to 10-9 sec range. Based on these measurements, a nanosecond, current switching, multiple coincidence system has been constructed. It is dc coupled and has input pulse limiters and clipping stubs. A ten-nonosecond scaler-discririnator stage is discussed which also employs current switching techniques. One output is scaled for pulse counting; another unscaled output is used to drive coincidence circuitry.