Uni junction transistor.pptx

electronics. UJT

1. SUBJECT : ELECTRONICS TOPIC : UJT PRESENTED BY :-

2. CONTENT What is UJT Construction Working V- I Characteristics

3. What is UJT ? Unijunction Transistor  is a semiconductor  switching device  having 2 layers and 3 terminals It is called so because of the presence of only  one junction . It has the ability to limit large power with a small input signal and is also known as a  double base diode .

4. Construction of UJT :- In Unijunction Transistor, the PN Junction is formed by lightly doped N type silicon bar with heavily doped P type material on one side. The ohmic contact on either ends of the silicon bar is termed as Base 1 (B 1 ) and Base 2 (B 2 ) and P-type terminal is named as emitter.

5. Working of UJT :- The N-type channel consists of two resistors RB1 and RB2 in series And a equivalent diode D representing the PN junction The emitter PN junction is fixed along the ohmic channel during its manufacturing process

6. Working of UJT :- The variable resistance RB1, is connected between the terminals Emitter (E) and Base1 (B1) , the RB2 between the Emitter(E) and Base2 (B2) Since the PN junction is more close to B2 , the value of RB2 will be less than the variable resistance RB1

7. Working of UJT :- The voltage across resistance RB1 of the voltage divider circuit is calculated by  

8. V – I Characteristics of UJT :-

9. Reference :- https://electricalfundablog.com/unijunction-transistor-ujt-construction-working-characteristics-curve-applications https://electricalfundablog.com/unijunction-transistor-ujt-construction-working-characteristics-curve-applications/