Method for Analysis of a Transistor Circuit

Method for Analysis of a Transistor Circuit

• In the previous section, we have seen generalized transistor circuit analysis using h-parameters. There are many transistor circuits. Circuits may consist of different biasing techniques, different configurations and so on. The analysis of such transistor circuits for its small signal behaviour can be made by following simple guidelines. These guidelines are :

1. Draw the actual circuit diagram.

2. Replace coupling capacitors and emitter bypass capacitor by short circuit.

3. Replace d.c. source by a short circuit. In other words, short V_CC and ground lines.

4. Mark the points B(base), C(collector), E(emitter) on the circuit diagram and locate these points as the start of the equivalent circuit.

5. Replace the transistor by its h-parameter model.

6. Check for exact analysis or approximate analysis if h_oe R_L > 0.1 use exact analysis otherwise use approximate analysis. The approximate analysis is discussed in the section 6.6.

Review Question

1. Give the guide lines for the analysis of transistor circuit for its small signal behaviour. Explain with an example.