Characteristics of unijunction transistor, Electrical Engineering

Characteristics of  unijunction transistor:

Characteristics : The static emitter characteristic of UJT at a given inter base voltage VBB in shown in fig. From fig., it is noted that for emitter potentials to the left of peak point, emitter current IE never exceeds IEO. The current IEO corresponds very closely to the reverse leakage current ICO of the conventional BJT. This region, as shown in the fig., is called the cut off region. Once conduction is established at VE = VP the emitter potential VE stars decreasing with the increase in emitter current IE. This corresponds exactly with the decrease in resistance current IE. The device, therefore, has a negative resistance region which is stable enough to be used with a great deal of reliability in the areas of applications listed earlier. Eventually, the valley point reaches, and any further increase in emitter current IE places the device in the saturation region, as shown in the fig. three other important parameters for the UJT are IP, VV and IV and are defined below :

Peak Point Emitter Current IP : It is the emitter current at the peak point. It represents the minimum current that is required to trigger the device. It is inversely proportional to the inter base voltage VBB.

Valley point Voltage VV : The valley point voltage is the emitter voltage at the valley point. The valley voltage increases with the increase in inter base voltage VBB.

Valley Point Current IV : The valley point voltage is the emitter voltage at the valley point. The valley voltage increases with the increase in inter base voltage VBB.

Special Features of UJT : The special features of a UJT are :

1. A stable triggering voltage a fixed fraction of applied inters base voltage VBB.

2. A very low value of triggering current.

3. A negative resistance characteristic.

4. Low cost.

Posted Date: 2/8/2013 2:56:35 AM | Location : United States







Related Discussions:- Characteristics of unijunction transistor, Assignment Help, Ask Question on Characteristics of unijunction transistor, Get Answer, Expert's Help, Characteristics of unijunction transistor Discussions

Write discussion on Characteristics of unijunction transistor
Your posts are moderated
Related Questions
Find the resistance of 1 km of copper cable having a diameter of 10 mm if the resistivity of copper is 0.017 x 10 -6 Ωm.

Discribe the ultrasonic machining with main emphasis on the following (a) Basic working Principle and machining set up (b) Accuracy and surface complete on work materials

A feedback control system with the configuration of Figure has the following parameters: K p = 0.5 V/rad, K a = 100 V/V, K m = 2.7 × 10 -4 N·m/V, J = 1.5 × 10 -5 kg·m 2 , and

Derive the transfer function of ward Leonard System

what happens when we apply DC supply to transformer primary

Linearize the swing equations around an equilibrium point. Compute the transfer function from the input U to the output !. For which equilibria is the linearizes system stabl

Figure shows two first-order triangular finite elements used to solve the Laplace equation for electrostatic potential.  Find a local S-matrix for each triangle, and a global S-mat

how to make a matlab program for calculation of AT&C loss for perticular area

When I read the details of how a transformer works and apply those rules to a transformer where the primary core cross-sectional area is twice that of the secondary, I come up with

Test Schedule - Meter Testing The test schedule as per the Central Electricity Authority Regulations on Installation and Operation of Meters is given below. Table: Test S