Small Signal - Low frequency - Analysis of Common Base amplifier using hybrid model

 Small Signal - Low frequency - Analysis of Common Base amplifier.. Yes, the characteristics of a CB amplifier is analyzing using low frequency -small amplitude signal. Analysis of CE amplifier is in another post. Better to go through it before diving into this.

 As discussed in previous posts, analysis requires three steps - 1)Taking the circuit which is to be analyzed 2)obtaining the small signal model and 3)finding out equations for parameters helps to get approximate values and it in turn will help to predict the characteristics of the circuit.

Small Signal - Low frequency - Analysis of CE amplifier using hybrid π model

 Here we are stepping to a zone mostly liked by questioners for essay - Low frequency analysis of CE amplifier . Small signal analysis of common emitter amplifier can be done using hybrid π model. Here low frequency analysis is considered.

In order to do the analysis of certain circuit, first step is to draw the model of that circuit. This model will help us to easily find equations for certain parameters of the circuit. Usually, input and output resistances, voltage gain and current gain are these four parameters. The equations will give an idea about the approximate value of these parameters and this in turn will help us to comment about characteristics of the circuit.  

Let's start...

Small signal model of a circuit

'Small signal analysis of CE, CB, CC configurations using hybrid π model' is a major topic in 'Micro electronics syllabus'. To do the analysis of a circuit, first we have to draw a model for that particular circuit(CE,CB or CC).  How can we obtain a small signal model for a circuit?- It is explained below. 

Steps to obtain a model from corresponding circuit :

Transistor - small signal model and small signal parameters

Analog Circuits /Electronics Circuits syllabus is packed with models. 

( I can see twinkling in your eyes, but… plz don’t disappoint. Just scan through below lines.)

The model 

To study the behavior of a transistor for different input conditions, we make use of different transistor models. These models are designed by taking various parameters of transistor into consideration. Hence having the same behavior as that of the corresponding transistor. To test the behavior of a transistor for a new input condition, instead of conducting a practical experiment, these inputs are applied on the corresponding transistor model and outputs are measured. Thus 'the model' helps to predict the nature of a transistor(or circuit) for various input or bias conditions without actually wiring it.