Theory & Procedure, Transistor Characteristics Class 12 Notes | EduRev

Physics Class 12

Created by: Infinity Academy

Class 12 : Theory & Procedure, Transistor Characteristics Class 12 Notes | EduRev

The document Theory & Procedure, Transistor Characteristics Class 12 Notes | EduRev is a part of the Class 12 Course Physics Class 12.
All you need of Class 12 at this link: Class 12

Our Objective:

To study the static characteristic of a transistor (Common Emitter Configuration)

The Theory:

A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power. It is composed of semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current through another pair of terminals. Because the controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal.

Bipolar Junction Transistors

Bipolar Junction Transistors are transistors which are made up of 3 regions, the base, the collector, and the emitter. A small current entering in the base region of the transistor causes a much larger current flow from the emitter to the collector region. Bipolar junction transistors come in two main types, npn and pnp. A npn transistor is one in which the majority current carrier are electrons. Electron flowing from the emitter to the collector forms the base of the majority of current flow through the transistor. The other type of charge,holes, are a minority. pnp transistors are the opposite. In pnp transistors, the majority current carriers are holes.

The circuit diagram for npn transistor is shown below.

Theory & Procedure, Transistor Characteristics Class 12 Notes | EduRev

Transistor characteristics:

1) Input characteristics

Keeping the collector- emitter (VCE) voltage constant, the base- emitter (VBE) voltage is increased from 0 and the corresponding base current (IB) values are noted. This is repeated for increasing values of VCE. The family of curve obtained by plotting IB against VBE for each VCE value is called input characteristics.

                                    Theory & Procedure, Transistor Characteristics Class 12 Notes | EduRev

2) Output Characteristics

By keeping the base current (IB) constant, collector- emitter (VCE) voltage is varied and the corresponding IC values are obtained. This is repeated for increasing values of IB. The family of curves obtained by plotting IC against VCE for each value of IB is called output characteristics.

                                    Theory & Procedure, Transistor Characteristics Class 12 Notes | EduRev

Learning Outcomes:

Students understand the following terms:

  • Transistor
  • pnp and npn transistors
  • Transistor characteristics

Students will be able to do the experiment, once they understand the procedure.

Material required:

  • Rheostat
  • Voltmeter
  • Ammeter
  • Battery
  • One way key
  • Transistor
  • Bread board

Real Lab Procedure:

  • Connections are made as shown in the circuit diagram.

    Theory & Procedure, Transistor Characteristics Class 12 Notes | EduRev

  • The rheostat Rh1 is used to vary base voltage (input voltage) VBE and it is read from voltmeter V1. The base current (input current) IB is measured using a microammeter (µA). The collector voltage (output voltage) VCE is varied using the rheostat Rh2 and readings are noted from voltmeter V2. The collector current (output current) IC is measured by the milliammeter (mA).

Input Characteristics

  • The collector voltage VCE is kept constant (eg. 1V) by adjusting the rheostat Rh2.
  • The base voltage VBE is varied from zero by adjusting the rheostat Rh1.
  • The base current IB is noted in each step.
  • A graph is drawn with VBE along X-axis and IB along Y-axis.
  • The experiment is repeated with VCE kept constant say 2V, 3V, 4V etc. and corresponding graphs are plotted. 

                                   Theory & Procedure, Transistor Characteristics Class 12 Notes | EduRev           

Output characteristics

  • The base current IB is kept constant (eg. 20µA) by adjusting the rheostat Rh1.
  • Now the collector voltage is increased by adjusting the rheostat Rh2.
  • The corresponding collector current IC is noted.
  • A graph is drawn with VCE along X-axis and IC along Y-axis.
  • The experiment is repeated with keeping IB constant, say 40µA, 60µA, 80µA etc and similar graphs are plotted.

                                     Theory & Procedure, Transistor Characteristics Class 12 Notes | EduRev

Observations:

Input characteristics

VCE (1V)
VBE (V)
 
 
 
IB (μA)
 
 
 
VCE (2V)
 
 
 
 
VCE (3V)
 
 
 
 
VCE (4 V)
 
 
 
 


Output characteristics

IB (μA)
VCE (V)
 
 
 
IC (mA)
 
 
 
IB (μA)
 
 
 
 
IB (μA)
 
 
 
 
IB (μA)
 
 
 
 


Results:

The graphs shows the input and output characteristics of a transistor.

Offer running on EduRev: Apply code STAYHOME200 to get INR 200 off on our premium plan EduRev Infinity!
204 videos|288 docs|125 tests

Content Category

Related Searches

Important questions

,

Objective type Questions

,

mock tests for examination

,

Transistor Characteristics Class 12 Notes | EduRev

,

Free

,

MCQs

,

Theory & Procedure

,

past year papers

,

shortcuts and tricks

,

practice quizzes

,

video lectures

,

Transistor Characteristics Class 12 Notes | EduRev

,

Extra Questions

,

Sample Paper

,

Summary

,

Exam

,

Viva Questions

,

Transistor Characteristics Class 12 Notes | EduRev

,

Previous Year Questions with Solutions

,

Theory & Procedure

,

pdf

,

Semester Notes

,

study material

,

ppt

,

Theory & Procedure

;