What are UJT and its characteristics?
The device has a unique characteristic that when it is triggered, its emitter current increases regeneratively until it is restricted by emitter power supply. It exhibits a negative resistance characteristic and so it can be employed as an oscillator. The UJT is biased with a positive voltage between the two bases.
What is an UJT explain its construction and characteristics explain the UJT as relaxation oscillator?
Advertisements. An oscillator is a device that produces a waveform by its own, without any input. Though some dc voltage is applied for the device to work, it will not produce any waveform as input. A relaxation oscillator is a device that produces a non-sinusoidal waveform on its own.
What is the main function of Unijunction Transistor UJT?
The Unijunction Transistor or UJT for short, is another solid state three terminal device that can be used in gate pulse, timing circuits and trigger generator applications to switch and control either thyristors and triac’s for AC power control type applications.
What is the application of UJT?
The unijunction transistor (UJT) used as relaxation oscillator. It is used as voltage detector. The UJT is used for switching. It is widely used as triggering device for silicon control rectifier (SCR) and TRIAC.
What is the other name of UJT?
What is the difference between UJT and put?
The PUT characteristics are similar to those of the UJT, the major differences being that the reverse leakage current (gate to anode) is much lower, and the on resistance is much lower. The PUT characteristics are shown in Figure 3. The transition from the off to the on state is also faster in the PUT than in the UJT.
What is the principle of UJT oscillator?
UJT Relaxation Oscillator consists of a UJT circuit with its emitter connected to a resistor and a capacitor. The timing of the output waveform is determined using the RC time constant. Supply voltage VBB is applied to the circuit. The capacitor starts charging through the resistor R1.
What is the principle behind UJT oscillator?
What are the advantages of UJT?
Advantages of Unijunction Transistor (UJT)
- low cost.
- negative resistance characteristics.
- Requires low value of triggering current.
- A stable triggering voltage.
- Low power absorbing device.
What are the characteristics of an UJT device?
The device has-a unique characteristic that when it is triggered, its emitter current increases re generatively (due to negative resistance characteristic) until it is restricted by emitter power supply. Since the device has one pn junction and three leads it is commonly called UJT. 1. Construction of a UJT
What are the characteristics of a complementary UJT?
A complementary UJT is formed by diffusing an N-type emitter terminal on a P-type base. Except for the polarities of voltage and current, the characteristics of a complementary UJT are exactly the same as those of a conventional UJT. The device has only one junction, so it is called the unijunction device.
Which is the basic arrangement for the UJT?
The basic arrangement for the UJT is shown in figure. A complementary UJT is formed by diffusing an N-type emitter terminal on a P-type base. Except for the polarities of voltage and current, the characteristics of a complementary UJT are exactly the same as those of a conventional UJT.
Which is the peak point of an UJT?
Peak-Point Emitter Current. Ip. It is the emitter current at the peak point. It represents the rnimrnum current that is required to trigger the device (UJT). It is inversely proportional to the interbase voltage V BB.