The emitter tetrode

If two ohmic contacts are made to the thin emitter region of a transistor in the form of a ring around the periphery and a dot in the center, it is possible to vary the ratio of the emitted current density under the center dot to the emitted density under the ring by passing a transverse current radially through the emitter region. This makes it possible to reduce the surface losses in such a transistor esentially to zero, at some expense of increased base resistance. Such a controllable alpha makes possible feedback stabilization into an independent terminal. The essential theory of operation and experimental verification of the calculations are shown and discussed.