Encyclopedia of Electronic Components Volume 1

Chapter 27. unijunction transistor

discrete semiconductor > single junction > unijunction transistor

The unijunction transistor (UJT) and programmable unijunction transistor (PUT) are different internally, but are sufficiently similar in function to be combined in this entry.

Other related components

• diode (See Chapter 26)
• bipolar transistor (See Chapter 28)
• field-effect transistor (See Chapter 29)

What It Does

Despite their names, the unijunction transistor (UJT) and programmable unijunction transistor (PUT) are not current-amplification devices like bipolar transistors. They are switching components that are more similar to diodes than to transistors.

The UJT can be used to build low- to mid-frequency oscillator circuits, while the PUT provides ...