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What is breakover voltage?
forward-breakover voltage - the voltage at which a device enters the forward-blocking region. The voltage at which the SCR enters the forward-condition region. The value of Vbr(f) is maximum when (Ig=current in gate) Ig=0 and is designate Vbr(f0). When the gate current is increased, Vbr(f) decrease and is designated Vbr(f1), Vbr(f2), and so on, for increasing steps in gate current (Ig1, Ig2, and so on).
What is zener break down voltage?
The point in the forward operating region of the characteristic curve where conduction starts to increase rapidly is called Knee voltage of a PN Junction Diode.The breakdown voltage of a diode is the minimum reverse voltage to make the diode conduct in reverse.(or) Breakdown voltage is a parameter of a diode that defines the largest reverse voltage that can be applied without causing an exponential increase in the current in the diode.-- Dinakar
Why base emitter voltage is always constant?
The base-emitter voltage (V_BE) in a bipolar junction transistor (BJT) is typically around 0.7 volts for silicon transistors when in the active region. This voltage remains relatively constant because it is determined by the built-in potential of the semiconductor junction and the thermal voltage, which is influenced by temperature. As current flows through the junction, the V_BE adjusts slightly to maintain the balance of charge carriers, but it generally stays close to this value under normal operating conditions. Consequently, it is considered constant for practical purposes in circuit analysis.
How do you reverse bias base collector junction?
To reverse bias a base-collector junction in a bipolar junction transistor (BJT), you need to apply a positive voltage to the collector relative to the base for an NPN transistor (or a negative voltage for a PNP transistor). This involves connecting the collector terminal to a higher potential and ensuring the base terminal is at a lower potential. As a result, the depletion region at the base-collector junction widens, preventing current flow between the collector and base. This condition is essential for transistor operation in certain configurations, such as in cutoff mode.
Why there is no current in reverse bias condition?
Current flows in a reverse biased diode because diodes are not ideal. They do have leakage current and a breakdown voltage in reverse, just as they have a breakdown current in forward and a non-linear and non-parallel forward voltage to current curve. It is also possible that you are looking at a zener diode. A zener diode is specifically design to conduct at a certain voltage in reverse.
What is the zener region?
The zener region describes the area on the performance curve (a graph of voltage across versus current through the junction) of a zener diode. The diode acts like a "regular" diode in the forward biased direction. When some 0.7 volts or so is reached, forward current begins to climb rapidly as voltage is increased (for silicon diodes.) But in the reverse direction recall that as the diode is reverse biased, a small amount of current will flow (because of minority carriers). This "trickle" of current will continue until the "zener voltage" is reached, and then the diode will begin to conduct heavily. On the graph, this is the zener region. Zener diodes can be made to breakdown at a specific voltage, and their ability to conduct reverse current can be increased by manufacturing a larger diode. That means there are a range of voltages and wattages of zener diodes available. Wikipedia has more information and that graph. Use the link provided to get there.
What is breakdown region?
The breakdown region of a transistor is the region where the supply voltage, Vcc, becomes so large that the collector-emitter junction of the transistor breaks down and conducts, even though there is no base current.
What is deplition region in a semiconductor?
Depletion region: Consider a diode .It is a basic semiconductor.It has two regions .A cathode (Negative-N) and anode(Positiv-P) regions.The N and P when connected together forms a diode.A junction will be created at the intersection of N and p regions .N region has electrons(-ve charge) and P region has holes(+ve charge) .At the junction the electrons from N region and holes from P region will join together .Particular area at the junction will have no charged particles after that.This region is called depletion region. If we give a voltage of 0.7V ,the depletion region will decrease and there will be current flow in the device.That voltage is called thershold voltage.
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.
What is the role of the quasi-neutral region in a PN junction and how does it contribute to the overall behavior of the junction?
The quasi-neutral region in a PN junction helps balance the concentration of charge carriers (electrons and holes) on both sides of the junction. This region allows for the flow of current by providing a pathway for the charge carriers to move across the junction. It contributes to the overall behavior of the junction by facilitating the formation of an electric field that helps regulate the flow of current through the junction.
What is forward breakover voltage?
forward-breakover voltage - the voltage at which a device enters the forward-blocking region. The voltage at which the SCR enters the forward-condition region. The value of Vbr(f) is maximum when (Ig=current in gate) Ig=0 and is designate Vbr(f0). When the gate current is increased, Vbr(f) decrease and is designated Vbr(f1), Vbr(f2), and so on, for increasing steps in gate current (Ig1, Ig2, and so on).
What is breakover voltage?
forward-breakover voltage - the voltage at which a device enters the forward-blocking region. The voltage at which the SCR enters the forward-condition region. The value of Vbr(f) is maximum when (Ig=current in gate) Ig=0 and is designate Vbr(f0). When the gate current is increased, Vbr(f) decrease and is designated Vbr(f1), Vbr(f2), and so on, for increasing steps in gate current (Ig1, Ig2, and so on).
What is the voltage required to turn on a silicon transistor?
basically a .6v to .7v is required to saturate the transistor The collector to emitter region will begin to become conductive once the base emitter junction is forward biased enough. Depending on the current through the base-emitter junction, the forward voltage drop could be anywhere from around .55 to .8 volts. .6 to .7 volts minimum is a good approximation not taking into account the device characteristics. Bipolar transistors (npn pnp) are current to current devices not voltage to current. This is for silicon transistors, germanium devices are lower forward voltage devices. Around .3 volts.
What is zener break down voltage?
The point in the forward operating region of the characteristic curve where conduction starts to increase rapidly is called Knee voltage of a PN Junction Diode.The breakdown voltage of a diode is the minimum reverse voltage to make the diode conduct in reverse.(or) Breakdown voltage is a parameter of a diode that defines the largest reverse voltage that can be applied without causing an exponential increase in the current in the diode.-- Dinakar
What is breakdown voltage of diode?
The critical value of the voltage, at which the breakdown of a P-N junction diode occurs is called the breakdown voltage.The breakdown voltage depends on the width of the depletion region, which, in turn, depends on the doping level. The junction offers almost zero resistance at the breakdown point.
Why base emitter voltage is always constant?
The base-emitter voltage (V_BE) in a bipolar junction transistor (BJT) is typically around 0.7 volts for silicon transistors when in the active region. This voltage remains relatively constant because it is determined by the built-in potential of the semiconductor junction and the thermal voltage, which is influenced by temperature. As current flows through the junction, the V_BE adjusts slightly to maintain the balance of charge carriers, but it generally stays close to this value under normal operating conditions. Consequently, it is considered constant for practical purposes in circuit analysis.
How do you explain the stability of output voltage in spite of input voltage changing at zener diode?
In the zener region of a diode, there is a relatively flat, low slope line for voltage as a function of current. As a result, increasing current in the zener region does not result in a significant increase in voltage - hence, voltage stability.
