UNI-JUNCTION TRANSISTORS (UJT’s)

A uni-junction transistor (UJT) is an electronic semiconductor device that has only one junction. The UJT has three terminals: an emitter (E) and two bases (B1 and B2). The base is formed by lightly doped n-type bar of silicon. Two ohmic contacts B1 and B2 are attached at its ends. The emitter is of p-type and it is heavily doped. The resistance between B1 and B2, when the emitter is open-circuit is called interbase resistance (RBB or r’BB).   Unijunction Transistor has different characteristics from ordinary bipolar transistor. It is a pulse generator with the trigger or control signal...