Where is UJT used?
Where is UJT used?
The UJT is not used as a linear amplifier. It is used in free-running oscillators, synchronized or triggered oscillators, and pulse generation circuits at low to moderate frequencies (hundreds of kilohertz). It is widely used in the triggering circuits for silicon controlled rectifiers.
What is the importance of programmable unijunction transistor?
In a UJT, the parameters like Vp, η etc are fixed and we cannot change it. The main application of programmable UJT are relaxation oscillators , thyristor firing, pulse circuits and timing circuits. ON Semiconductor® is the only manufacturer of PUT now.
How does a Unijunction transistor work?
The Unijunction Transistor (UJT) will act as voltage breakdown device, when the input applied between emitter and base 1 reduces below breakdown value i.e., RB1 increases to a higher value. This shows that RB1 depends on the emitter current and it is variable.
What are unijunction transistor used for MCQ?
The uni-junction transistor is a solid-state three-terminal device that can be used in gate pulse, timing circuits, and trigger generator applications to switch and control both thyristors and triacs for AC power control type applications.
Why is UJT known as a unijunction transistor?
Definition: Unijunction Transistor is a semiconductor switching device having 2 layers and 3 terminals and is abbreviated as UJT. 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.
Why UJT is called unijunction?
The UJT consists of an n-type silicon semiconductor bar with an electrical on each end. Since the device has three terminals and one pn-junction, for this region this is called as a Unijunction Transistor (UJT).
What are the possible applications of put?
Applications for PUTs include:
- thyristor triggers.
- oscillators.
- pulse.
- timing circuits with frequencies up to 10 kHz.
What are the application of DIAC?
The DIAC is an electronics component that is widely used to assist even triggering of a TRIAC when used in AC switches and as a result they are often found in light dimmers such as those used in domestic lighting. These electronic components are also widely used in starter circuits for fluorescent lamps.
Is a unijunction transistor a continuous variable device or a switching device?
Unijunction Transistor (UJT): A unijunction transistor (abbreviated as UJT) is a three-terminal semiconductor switching device. This device has a unique characteristic that when it is triggered, the emitter current increases regeneratively until it is limited by emitter power supply.
What are some of the characteristics of transistor and unijunction transistor?
The special features of a UJT are :
- A stable triggering voltage (VP)— a fixed fraction of applied inter base voltage VBB.
- A very low value of triggering current.
- A high pulse current capability.
- A negative resistance characteristic.
- Low cost.
What are unijunction transistors used for 1 point?
Explanation: A unijunction transistor consists of three terminals. It is a semiconductor device that displays negative resistance and switching characteristics. It is used as a relaxation oscillator in phase control applications.
What are the active region of a unijunction transistor?
A unijunction transistor consists of two bases (B1, B2) attached to a resistive bar of silicon, and an emitter in the center.
