Transistors – Notes – 1

1. Transistors are three terminal devices that can be formed with the combination of two separate PN junction materials into one block.

2. An NPN transistor is formed with two PN junctions with the P−type material at the center, whereas a PNP transistor is formed with two PN junctions with the N−type material at the center.

3. The three terminals of a transistor, whether it is an NPN or PNP transistor, are identified as the emitter, the base, and the collector.

4. Transistors are used either as amplifiers or as electronic switches.

5. Like junction diodes, most transistors are made of silicon. Gallium Arsenide (GaAs) technology has been under development for several years and its advantage over silicon is its speed, about six times faster than silicon, and lower power consumption. The disadvantages of GaAs over silicon is that arsenic, being a deadly poison, requires very special manufacturing processes.

6. Since a transistor is a 3−terminal device, there are three currents, the base current, denoted as iB, the collector current, denoted as  iC, and the emitter current, denoted as  iE

7. For any transistor, NPN or PNP, the three currentsare related as :

iB + iC = iE

8. A very useful parameter in transistors is the common−emitter gain β , a constant whose value ranges from 75 to 300. Its value is specified by the manufacturer. The base current  iis much smaller than the collector current iC and these two currents are related in terms of the constant β as :

iB = iC/β

9. Another important parameter in transistors is the common−base current gain denoted as α and relates the collector and emitter currents as :

iC = αiE

10. The parameters  and  are related as :

α = β/1 + β

β = α/1 – α

Transistors – Mcq
Transistors – Notes
Transistors – IQ

Be a Part of The New & Next

MCQs fb  MCQs G+

Share the Knowledge

GATE Total InfoGATE 2019 BooksFree Notes
IES Total InfoIES 2019 BooksFree Mock tests
JAM Total InfoJAM 2019 BooksEngg Diploma
PSUs Total InfoM Tech Total InfoUGC NET Total Info
Aerospace EngineeringCivil Engineering Physics
Geology and GeophysicsMining EngineeringComputer Science
Agricultural Engineering Chemical Engineering Architecture and Planning
Instrumentation EngineeringMetallurgical EngineeringElectrical Engineering
Production and Industrial EngineeringElectronics and Communication EngineeringTextile Engineering and Fibre Science
MathematicsInformation TechnologyEngineering Sciences
Biotechnology Petroleum EngineeringLife Sciences
Mechanical EngineeringChemistry
What is is an online forum for multiple choice questions. This forum would be really-really helpful for those candidates who are preparing for various technical as well as non-technical examinations.


Here at you will find all important Mcqs, Notes, Interview Questions useful for Union Public Service Commission (like Civil Services Examination, Engineering Services Examination, Special Class Railway Apprentice, National Defence Academy, Combined Defence Services, etc.), Staff Selection Commission (like Combined Graduate Level, Junior Engineer, Food Corporation of India etc.), various public sector units (like DRDO, DMRC, BARC, BSNL, ONGC, etc.), Graduate Aptitude Test in Engineering (GATE), Indian Institute of Technology Entrance Examination(IIT-JEE) etc. and many other national and state level examination.

Leave a Reply

Your email address will not be published. Required fields are marked *

Copy Protected by Chetan's WP-Copyprotect.