Transistor Biasing Circuits
George Domingo · 2020
This chapter explains how we use transistors, how we bias them, so they generate working and useful circuits, and how we stabilize them as the temperature, currents, and applications vary. There are several ways we can bias a transistor: fixed base bias, collector feedback bias, and emitter feedback bias. The chapter focuses on the basic operation of a single transistor and discusses the operational amplifier (OpAmp), a “single component”, which is more stable and easier to insert in a circuit without much need for design and calculations. An ideal OpAmp can have the following characteristics: infinite input resistance, infinite gain, and zero output resistance. By isolating or shorting portions of the circuit using capacitors, sinusoidal voltages can be amplified without disturbing the DC conditions that make the transistor functional and stable.