What is BJT, Definitions, Advantages & Disadvantages

Authored By: Ankita Prajapati

BJT stands for Bipolar Junction Transistor. It is an electronic component that controls current flow between two terminals by using a small current applied to a third terminal. It is a semiconductor device, which is made of two layers of a semiconductor material, such as silicon, with different doping concentrations. 

These two layers are called emitter and collector, and the third terminal is called the base.

When the base current is applied, the emitterbase junction is forward biased, and the collectorbase junction is reverse biased.

This allows the current to flow from the emitter to the collector. The amount of current flowing from the collector to the emitter is controlled by the base current.

This current flow is known as amplification, because the small base current is amplified to control a much larger collector current. BJTs can be used in a variety of applications, such as amplifiers, switches, oscillators, and other digital circuits. They are also commonly used as transistors in power supplies.

BJTs are more efficient than other types of transistors, and they are more reliable and can handle higher power levels. BJTs are widely used in consumer electronics, such as computers, televisions, radios, and other electronic devices.

Learn the concepts of BJT with YourEngineer


  1. Low cost
  2. High switching speed
  3. High input impedance
  4. Wide range of current gain 
  5. Good linearity and low distortion 
  6. Low noise.ts
  7. Easy to interface with other componen


  1. High power consumption
  2. Limited current and voltage handling capabilities 
  3. Poor frequency response 
  4. Prone to thermal and secondary breakdowns 
  5. Susceptible to latchup problems

Test your ANSYS skills with YourEngineer


They are also used in industrial and medical applications, such as power supplies, medical imaging, and medical diagnostics.

BJTs have evolved over time, and they continue to be improved to meet the demands of modern electronics. They are reliable, efficient, and costeffective, and they continue to play an important role in todays electronic devices.

What is YourEngineer?

YourEngineer is the first Engineering Community Worldwide that focuses on spreading Awareness, providing Collaboration and building a focused Career Approach for Engineering Students.

Deep dive into Engineering, Join millions like you

campus cover

Apply for Upcoming Programs:

Career Building Program

21-Day Career Building and Advancement BootCamp

Join this 21 Day Bootcamp starting from 01st Feb 2023 and transform yourself.

Skill Development Program

Full Stack Development Training Program (Basic to Advanced)

Become a Full Stack Developer today with 100% Placement Guarantee.

  • Create an Account and Earn 1000 Coins
  • Pass a Quiz and Earn 20 Coins
  • Earn 10 Coins for Daily Visit 
  • Earn 50 Coins for invite someone to join a group
  • Earn 100 Coins for finishing a course