Draw and explain the UJT characteristics?

1. What is UJT and its symbol?
2. What is an UJT and draw its equivalent circuit?
3. What is the main function of UJT?
4. What are the advantages of a UJT?
5. How is a UJT constructed?
6. What is UJT explain?
7. How UJT differs from BJT and draw the symbol of UJT?
8. What is the difference between UJT and put?
9. What is UJT explain its construction and working also explain its characteristics?
10. Why UJT is called transistor?
11. What is the principle behind UJT oscillator?
12. Why UJT is used as relaxation oscillator?
13. What is DC load line and Q point?
14. When a UJT is used for triggering of an SCR the wave shape of the voltage is a <UNK> wave?

What is UJT and its symbol?

The symbol of UJT is designed in such a way that arrow is bent and shown that it is in the direction towards the channel. It resembles of JFET. If the channel is made of the N-type then the terminal called emitter is of P-type and vice-versa.

What is an UJT and draw its equivalent circuit?

The working of UJT can be understood by its equivalent circuit. The voltage applied at the emitter is indicated as V_E and the internal resistances are indicated as R_B1 and R_B2 at bases 1 and 2 respectively. Both resistances present internally are together called as intrinsic resistance, indicated as R_BB.

What is the main function of 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 are the advantages of a UJT?

Advantages of Unijunction Transistor (UJT)

low cost. negative resistance characteristics. Requires low value of triggering current. A stable triggering voltage.

How is a UJT constructed?

Construction of UJT

The UJT consists of an n-type silicon semiconductor bar with an electrical on each end. The terminals of these connections are called Base terminals (B₁ and B₂). Near to base B₂, a pn-junction is formed between a p-type emitter and the n-type silicon bar.

What is UJT explain?

A unijunction transistor (UJT) is a three-lead electronic semiconductor device with only one junction that acts exclusively as an electrically controlled switch. The UJT is not used as a linear amplifier.

How UJT differs from BJT and draw the symbol of UJT?

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.

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 UJT explain its construction and working also explain its characteristics?

A Unijunction Transistor (UJT) is a three terminal semiconductor switching device. ... A Unijunction Transistor is constructed by forming a pn- Junction between a lightly doped N type silicon bar and a heavily doped P type material on one side as shown in the figure.

Why UJT is called 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.

What is the principle behind 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.

Why UJT is used as relaxation oscillator?

UJT is an excellent switch with switching times in the order of nanoseconds. ... The UJT relaxation oscillator is called so because the timing interval is set up by the charging of a capacitor and the timing interval is ceased by the rapid discharge of the same capacitor.

What is DC load line and Q point?

The DC load line is the load line of the DC equivalent circuit, defined by reducing the reactive components to zero (replacing capacitors by open circuits and inductors by short circuits). It is used to determine the correct DC operating point, often called the Q point.

When a UJT is used for triggering of an SCR the wave shape of the voltage is a <UNK> wave?

When a UJT is used for triggering an SCR, the wave shape of the voltage obtained from the UJT circuit is a saw-tooth wave.