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Why ujt called current controlled negative resistance device?
The On/OFF action in UJT is controlled by emitter current
Operation of UJT and block diagram?
Explaine operation of UJT .
How to genrate sawtooth wave by using ujt?
by connecting the ujt with proper biasing resistors
How does a ujt relaxation oscillator work?
The operation of the circuit is as follows: C1 charges through R1 until the voltage across it reaches the peak point. The emitter current then rises rapidly, discharging C1 through the base 1 region and R3. The sudden rise of current through R3 produces the voltage pulse. When the current falls to IV the UJT switches off and the cycle is repeated.
Draw and explain the UJT characteristics?
The Unijunction emitter current vs voltage characteristic curve figure(a) shows that as VE increases, current IE increases up IP at the peak point. Beyond the peak point, current increases as voltage decreases in the negative resistance region. The voltage reaches a minimum at the valley point. The resistance of RB1, the saturation resistance is lowest at the valley point.Ip and Iv, are datasheet parameters; For a 2n2647, IPpand IVvare 2µA and 4mA, respectively. Vp is the voltage drop across RB1 plus a 0.7V diode drop; see Figure (b). Vv is estimated to be approximately 10% of VBB.
Characteristiccs of UJT?
The characteristics of a UJT are: stable triggering voltage, negative resistance, high pulse current capability and low value of triggering current.
Why ujt called current controlled negative resistance device?
The On/OFF action in UJT is controlled by emitter current
What are the advantages and disadvantages of UJT?
The advantages of a UJT include low cost, a negative resistance characteristic, and a low value of triggering current. The main disadvantage is the inability to provide decent amplification.
What is inter base resistance in UJT?
The bulk resistance between the two bases, which will be different for different types of UJT. Consult the datasheet for the value.
Why name of the device is UJT?
UJT means Uni Junction transistor terminals are Emitter,Base1 and Base2.UJT is also called double base diode.UJT operates when the emitter is forward biased.voltage is applied between base1 and base2.If an external voltage is applied at terminal E,no current will flow in to the emitter as long as this applied voltage is less than emitter voltage.When this applied voltage exceeds emitter voltage,current will flow into the emitter and holes get injected from emitter to base1 and are repelled by base2.This results in increase in the region between the junction and the base 1.The increase in conductivity results drop in emitter voltage and increased forward bias of the junction.so emitter current also increases.Then it exhibits a negative resistance.
Can UJT replace BJT?
No. A unijunction transistor (UJT) is entirely different in design and application than a bipolar junction transistor (BJT). The UJT works on the principle of voltage modulation of the effective substrate resistance, while the BJT works on the principle of current amplification from one junction to the other, usually base-emitter to collector-emitter.
Why ujt used as an oscillator?
why ujt used as amplifier
Operation of UJT and block diagram?
Explaine operation of UJT .
Is ujt is a uni polar transistor?
UJT is known as Uni Junction Transistor
Describe the difference between a UJT and a PUT?
i. Constructional structures The UJT is made up of a lightly doped n-region known as the base region onto which is joined a small heavily doped p-region called the emmitter. The PUT on the other hand is a four layer device similar to an SCR except that the gate terminal of the PUT is connected to the n-region adjacent to the anode. ii.Operation The intrinsic stand-off ratio of a UJT is fixed hence operating characteristics can not be alterd. The PUT, on the other hand has operating characteristics that can be altered. These include base-base resistance,intrinsic stand-off voltage, valley current and peak current and all these can be altered by setting the values of two external resistors
How to genrate sawtooth wave by using ujt?
by connecting the ujt with proper biasing resistors
In ujt what does the j stand for?
For many people the letters UJT stand for Unitary Junction Transistor.
