Transistor biasing principles from "summary" of Fundamentals of Electronics by Thomas F. Schubert,Ernest M. Kim
Transistor biasing is an essential concept for achieving optimal performance in electronic circuits. It involves adjusting the operating point of the transistor for proper voltage and current levels, resulting in reliable and consistent operation.- Biasing of a transistor is like setting up the operating parameters to make sure that it operates correctly. To do so an appropriate voltage or current must be applied to the transistor terminals.
- Common emitter type transistors are generally biased by constructing a voltage divider circuit and feeding the mid point of the voltage divider node with required bias voltage or current.
- Transistor biasing allows us to control the gain of the transistor along with the stability of the entire circuit configuration.
- Proper selection of resistor values in the bias circuit helps to achieve the desired DC bias conditions at the transistor base and emitter points.
- It is critical to establish the correct biasing conditions between the voltage, current and resistance at the transistor terminal connections. Otherwise, it may cause the transistor to malfunction.
- Adjustments may also be made in the biasing circuit based on the kind of amplifier designed to get the accurate results.
- In radio and electronics, a transistor can be biased to operate in different modes. Generally, it has three operating regions: cut-off region, active region and saturation region.
- To operate a transistor properly, we must find out its electrical characteristics graph – the I-V curve which provides the information about the various operating points of the device.
