18 Questions
The UJT structure consists of a heavily doped p-type silicon bar.
False
The two end connections of the UJT are called base B1 and base B2.
True
The UJT emitter forms a p–n junction with the bar.
True
The UJT can be reproduced, distributed, or transmitted without prior written permission of the owner.
False
The UJT is made entirely of a heavily doped n-region.
False
Recording of the UJT material is allowed for commercial purposes.
False
The UJT is mainly popular due to its low switching speed.
False
UJTs are commonly used in phase control and timing circuits.
True
Any form of reproduction of the material is allowed without prior permission.
False
IGBT combines the advantages of a power BJT and a power MOSFET.
True
The UJT is not used in oscillator circuit design.
False
Both power MOSFET and IGBT are the continuously controllable current-controlled switch.
False
The DIAC is a three-terminal device like the BJT.
False
In the DIAC, the emitter is highly doped, the collector is lightly doped, and the base is moderately doped.
False
The construction of DIAC closely resembles that of a transistor.
True
DIAC can be reproduced, distributed, or transmitted without permission for personal academic use.
True
In the BJT, all three layers are equally doped.
False
The DIAC is a four-terminal diode.
False
Study Notes
UJT (Unijunction Transistor)
- Consists of a lightly doped n-type silicon bar with ohmic contacts on either side
- Has a small heavily doped p-region (emitter) alloyed into one side of the bar, forming a p-n junction with the bar
- Has two end connections called base B1 and base B2
- Popular due to its high switching speed
- Applications:
- Triggering SCRs and TRIACs
- Non-sinusoidal oscillators
- Phase control and timing circuits
- Saw tooth generators
- Oscillator circuit design
IGBT (Insulated-Gate Bipolar Transistor)
- Combines the advantages of a power BJT and a power MOSFET
- A continuously controllable voltage-controlled switch
DIAC (Diode AC Switch)
- Construction is similar to a transistor but with major differences
- All three layers (p-n-p or n-p-n) are equally doped
- A two-terminal diode, unlike the three-terminal BJT
- No gradation of doping; emitter is highly doped, collector is lightly doped, and base is moderately doped
Test your knowledge on the applications of the Unijunction Transistor (UJT). Learn about how the UJT is utilized to trigger SCRs and TRIACs for various electronic functions.
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