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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.
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In ujt what does the j stand for?
For many people the letters UJT stand for Unitary Junction Transistor.
What safety device is fitted to ensure a circuit breaker can not be racked out when closed?
A remote racking device is the name of a safety device that is fitted to ensure a circuit breaker cannot be racked out when closed.
Characteristics of relaxation oscillator?
A "Relaxation Oscillator" is an "R/C" oscillator, in which a Capacitor is charged from a DC (Direct Current) fixed voltage source, through a resistor. Connected across this Capacitor is a "device" that, initially, does NOT conduct any current. But when the Voltage on the Capacitor reaches a certain value (depending upon the characteristics of the "device") the "device" will "break down" or "avalanche", or suddenly drastically decrease in resistance. This causes the "device" to quickly start to discharge the Capacitor. However, when the Voltage across the Capacitor and its parallel connected "device' decreases with the discharge cycle, the "device" will suddenly return to its "non-conducting" state, and the Capacitor again begins to re-charge. The Capacitor again reaches the "break down" voltage of the "device", and the process continues, thus effectively creating "oscillations". One version of this circuit uses a simple Neon lamp (such as a NE-1) as the "device". Typically, the "break down" or "ignition" voltage of a neon lamp is around 70 volts. At this point, the gas in the lamp "ionizes", becoming highly conductive. However, when this voltage drops (as the lamp discharges the Capacitor) to about 50-60 volts, the lamp "goes out" (the neon gas is no longer ionized or conducting), and the Capacitor again starts to charge through the resistor. This form of the "Relaxation Oscillator" will not operate at high frequencies (such as Radio Frequencies), and was often used to just generate a "flashing light" (the Neon lamp). With the advent of semiconductors, a device called the Unijunction Transistor (UJT) was developed. It contained three leads, the Emitter, Base 1, and Base 2. The junction of the Resistor and Capacitor is connected to the Emitter, with the "bottom" of the Capacitor (and the negative side of the Voltage Source) connected to Base 1 Base 2 is connected to the positive side of the Voltage Source. Again, when the voltage on the Capacitor reaches the "break down" level, the UJT's "resistance" between the Emitter and Base 1 drastically drops, discharging the capacitor. However, when the discharging current through the UJT drops below a certain level, it again develops a high resistance between its Base 1 and the Emitter, and re-charging of the Capacitor begins again. UJT circuits can operate at higher frequencies than the Neon bulb circuit. Often a resistor is inserted between Base1 and the common or negative side of the voltage source, and the resulting discharge current produced voltage across this resistor is used to trigger other devices. Also, the voltage waveform across the Capacitor approaches a linear "sawtooth" waveform (depending on circuit component values), but not nearly as linear as other approaches. "Devices" of this type are considered to have a "negative resistance" characteristic, which is another discussion in itself.
What is the main function of a power supply unit?
The name tells you - it supplies power to the device it is part of.
What is the name of the episode where Maggie Simpson gets talking device?
Brother, Can You Spare Two Dimes?
Why ujt called current controlled negative resistance device?
The On/OFF action in UJT is controlled by emitter current
Difference between bjt and ujt?
UJT is the voltage controlled device.in which only one mejority carriers are responsible for current flowing. UJT is one junction transistor and it is three terminal emitter and two base. BJT is the current controlled device. in which both mejority and minority carrier are responsiblefor current flowing. this type of transistor consists of two junction and three terminal these are : emitter , base , collector.
How do you make ujt with npn and pnp transistors?
You dont. A UJT is a much simple device than either of those BJT's Maybe you want to make a multivibrator out of BJT's?
Is a UJT a voltage controlled or current controlled device?
voltageCurrent between the two bases of the UJT sets up a voltage gradient in the semiconductor. When the voltage on the emitter of the UJT rises high enough to forward bias the emitter-base junction at the voltage of the interbase gradient where the emitter is located, the UJT "turns on".
What is a UJT?
UJT(UNIJUNCTION TRANSISTOR) is a three-lead electronic-semiconductor device with only one junction that exclusively as an eletrically controlled swtich andit is not used as a linear amplifier.
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
How to genrate sawtooth wave by using ujt?
by connecting the ujt with proper biasing resistors
Why UJT is called as transistor?
Even though it has only two types of charge carriers we will not call it as a diode but a transistor since it is a three terminal device.
In ujt what does the j stand for?
For many people the letters UJT stand for Unitary Junction Transistor.
Can ujt be used to trigger scr?
no
