Junction gate static induction transistor (JSIT) is designed as normally-off device, where the channel is completely pinched-off by the gate to channel built-in voltage, thus establishing a potential barrier in the channel. An application of forward gate bias voltage lowers the potential barrier and allows the drain current to flow. This normally-off JSIT is called bipolar mode SIT (BSIT). Basic characteristics of BSIT is similar to that of bipolar transistor. BSIT is characterized by low impedance, high current gain, high transconductance and high current density, so that BSIT is promising for high current, high speed and high efficiency switching devices as well as low voltage and low energy integrated circuits.
Basic operational principle of BSIT is described by feedback theory with a consideration to the virtual base resistance.