Semiconductor Control Devices
Bryan Norris · 1972
A unijunction transistor (UJT) is a three-terminal device exhibiting a stable incremental negative resistance region under certain conditions. This negative resistance makes possible the design of unique switching circuits comprising fewer components than comparable transistor circuits. The input impedance of the UJT in the off state is high— in the order of 5 megohms — making the UJT suitable for high input impedance voltage sensing circuits.