UJT is not used for:

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RRB ALP Electronics Mechanic 21 Jan 2019 Official Paper (Shift 3)
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  1. timing circuits
  2. phase control
  3. triggering an SCR/TRIAC
  4. amplification

Answer (Detailed Solution Below)

Option 4 : amplification
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The correct answer is option 4.

Unijunction Transistor (UJT)

F1 Savita Engineering 2-7-22 D34

UJT is a two-layered, three-terminal, solid-state switching device. Unlike a BJT, it has only one junction that's why it is called Unijunction Transistor.

UJT can act as an electrically operated solid-state switch. 

UJT is also known as a double base diode because like a diode it also has two-layer and one junction. Just difference is diode has two terminals whereas UJT has three terminals.

Application and Uses of UJT

  1. The main application of UJT is, it is used for triggering SCR and TRIAC.
  2. These are used in synchronized oscillators, and pulse generator circuits that work at low to moderate frequencies.
  3. It is used in digital voltage and frequency measurement circuits.
  4. These are used to make relaxation oscillator circuits.
  5. These are used in phase control and timing circuits.
  6. These are used for different types of waveform generation such as Sawtooth Wave generation.
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