Analog Electronic Circuits

Transistor Biasing and Stability

Question
11 out of 14

What is punch-through effect?

With the increase in collector voltage, effective base width is reduced to zero, and the emitter barrier voltage becomes smaller than Vo |VEB| as the collector voltage reaches through the base region. Due to lowering of emitter junction voltage, an extensively large emitter current flows. Therefore, there is an upper limit on the magnitude of collector voltage. This phenomenon is called punch-through.