Study Input and Output Characteristics of Transistor in Common Emitter Configuration

Title

Input and output characteristics of transistor in common emitter configuration.

Objectives:

Components and equipments required:Trainer kit, multimeter and connecting wires.

General Instructions:You will plan for Experiment after self study of Theory given below, before entering in the Lab.

Theory:

A transistor consist of two PN junctions formed by sandwiching P-type or N-type semi - conductor between a pair of opposite type.

According there are two pairs of transistor namely:

1. n-p-n transistor
2. p-n-p transistor

A transistor has three terminals:

1. Emitter
2. Base
3. Collector

The emitter is heavily doped so that it can input a large number of change carriers into base. The base is lightly doped and varies thin passes that most of the emitter injected charge carriers to the collector .The collector is moderately doped .The junction between emitter and base called emitter-base junction. The junction between the collector and base may be called as collector –base junction. The emitter junction is always forward biased and collector junction is always reversed biased. A transistor transfer a low resistance circuit to high resistance circuit and hence the name

Trans → transfer, istor → resistance.

Common Emitter Configuration

In this circuit arrangement, input is applied between base and emitter and output is taken out from collector and emitter. Thus emitter is common terminal for input and output signals. Therefore, such circuitry is known as common emitter –configuration.

Procedure:-

1. Connect the circuit as shown in this circuit diagram.
2. For input characteristic
• Keeping VCE constant (say 1V ),note down the base current IB for various of VBE.
• Then plot the reading obtained on a graph taking IB along Y-axis and VBE along X-axis.
3. Repeat the procedures of VCE = 4V or Above 4V.
4. For output characteristic
• Keeping IB current constant say(1 microampere) , note down the collector current IC for various values of VCE.
• Plot the reading on a graph taking IC along Y-axis & VCE along X-axis.
• Repeat the procedure for various values of IB.

Observation Table

Input characteristics:

Output characteristics:

Outputs:Submit the graph as per observation table.

Conclusion: