8 July 2020

Difference between UJT and BJT

The most significant difference between UJT and BJTis their applications, UJT can use as a switch in a circuit, and it has no application capabilities like BJT. While in BJT  can be used as either a switch or an amplifier. Here this article give the information about the main key difference between UJT and BJT to better understand this topic.

What is BJT?

A BJT stands for bipolar junction transistor is a three-layer, two junction NPN or PNP semiconductor device with one p-region sandwiched by two n-region, Its called NPN transistor. With two p-region sandwiched and one n-region, its called PNP transistor. 

What is UJT?

UJT stands uni-junction transistor, UJT has a three-terminal semiconductor switching device with only one junction that acts exclusively as an electronically controlled switch for use as a relaxation oscillator in the phase control applications.  

Difference between UJT and BJT:

  • UJT stands for unijunction transistor, while in BJT stands for bipolar junction transistor.
  • UJT is only one junction is present in BJT, while in BJT consist of two junctions. It is two junction transistors.
  • UJT is also known as double-base diode as contains two bases while in BJT contain three-terminal namely emitter, base, and collector.
  • UJT can be used as the voltage control device, But the BJT can be categorized as the current control device.
  • The conduction in this transistor is based on the flow of the majority of the carries through it, while in BJT the conduction in this transistor is completely based on the flow of both as majority and the minority carriers through it.
  • UJT can't be preferred for amplification, BJT can be used as amplifiers.
  • UJT is preferred for the switching application, While in BJT is based on the operating regions it can be preferred for amplification as well as suitable for the switching of the device.
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