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Why the current in zener diode is small in reverse biasing and why it is large in forward biasing?
Wiki User
∙ 11y ago
A zener diode is designed to allow a current to flow through it in a direction that is reverse to the normal flow of current that would occur if it were used as a rectifier. Current can flow through a zener diode in both directions. In the forward direction, current will flow at a low voltage, usually about 1 volt. In the reverse direction, no current will flow until the voltage impressed across it is equal to the zener voltage. At this point, a current will flow and an extremely small increase in voltage will cause a large increase in current. Most importantly, it should be noted that the current flow through the zener diode is in the reverse direction to that of a normal rectifier. With the application of sufficient reverse voltage, a p-n junction will experience a rapid avalanche breakdown and conduct current in the reverse direction. Valence electrons which break free under the influence of the applied electric field can be accelerated enough that they can knock loose other electrons and the subsequent collisions quickly become an avalanche. When this process is taking place, very small changes in voltage can cause very large changes in current. The breakdown process depends upon the applied electric field, so by changing the thickness of the layer to which the voltage is applied, zener diodes can be formed which break down at voltages from about 4 volts to several hundred volts.
Wiki User
∙ 16y ago
Wiki User
∙ 14y agoYes, a zener diode is normally operated in the reverse bias direction, cathode more positive than anode.
If you forward bias a zener diode, it acts like a normal diode, with a junction voltage between 0.6V and 0.7V, which is not what you want.
Wiki User
∙ 11y agoSure. When it's forward biased, it works just like any other silicon diode, with
anywhere between 0.7 to 1.1 volts across it. But that's not why you bought
a Zener. If you want to use it as a Zener diode, it only works that way when
it's reverse biased.
Wiki User
∙ 12y agoThe resistor in series with a zener diode operating in reverse breakdown mode is used to limit the current through the zener diode to the level it should be for stable operation.
Wiki User
∙ 11y agothe voltage drop is higher in a reverse bias configuration
Wiki User
∙ 11y agode
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What are the types of biasing in pn junction diode?
There are 2 type of biasing in PN junction didoe Forward biasing Reverse biasing
Is the banded end of a diode positive or negative?
The Banded end of diode represents Cathode.If you want the diode to be forward biased then the Cathode is made more negative than Anode.For reverse biasing of Diode (Zener Diode) The Cathode is kept positive.However the mail carrier of current in the Cathode is Electrons which are negative.
What type of biasing must be used when a zener diode is used as a regulator?
REVERSE biasing. Parvezctg2@gmail.com.BD
How are power diode classified?
by reverse breakdown voltage & forward current capacity
What is the behavior of a forward and reverse biased diode?
Forward Resistance:def: It is resistance offered by diode to the forward bias is known as forward resistance.This resistance is not the same for the flow of DC as for the changing current. Accordingly this resistance is of two types :1. DC FORWARD RESISTANCE.2. AC FORWARD RESISTANCE.1. DC forward resistance: It is the opposition by diode to the DC. It is measured by the ratio of DC voltages across the diode to the resulting DC current through it.2. AC forward resistance: It is the opposition offered by the diode to the changing current. It is measured by the ratio of change in voltage across diodes to the resulting change in current through diode. The AC forward resistance is more significant as the diodes are generally used with alternating voltage.Reverse Resistance:def: The resistance offered by the diode to the reverse bias is known as Reverse Resistance. It can be DC reverse resistance or AC reverse resistance depending upon whether the reverse bias is direct or changing voltage. Idealy the reverse resistance of a diode is infinte however in practice the reverse resistance is not infinite because for any value of reverse bias, there does exist a small leakage current. It may be emphasized their that reverse resistance is very large compared to the forward resistance.These Definitions are from PRINCIPLES OF ELECTRONICS by V.K MEHTA and ROHIT MEHTA
What are the types of biasing in pn junction diode?
There are 2 type of biasing in PN junction didoe Forward biasing Reverse biasing
Explain the working principal of diode with diagram?
A diode when forward biased will allow the flow of current while reverse biasing will cut off the flow of current. It is the basic building block of any semiconductor.
Is the banded end of a diode positive or negative?
The Banded end of diode represents Cathode.If you want the diode to be forward biased then the Cathode is made more negative than Anode.For reverse biasing of Diode (Zener Diode) The Cathode is kept positive.However the mail carrier of current in the Cathode is Electrons which are negative.
What is forward and reversed biasing?
This is a characteristics of semiconductor diode {pn junction}.In forward biasing here we connect p to positive terminal and n -ve terminal when external voltage is aplied in such a direction that cancels out potential barrier thus permitting current flow In reverse biasing the connection of pn junction is inverted but in this the potential barrier incresesand offers resistance to current flow but at a certain voltage current increases suddenly(the break down voltage)the zener diode works in this principle
Why diode conducts current in forward bias but does not conduct in reversed bias?
diode current flows only when the diode is forward biased because in reverse bias the barrier potential increases. Diode can conduct in reverse bias if applied votage is high enough to overcome the reverse bias barrier potential but it can be destructive.
What type of biasing must be used when a zener diode is used as a regulator?
REVERSE biasing. Parvezctg2@gmail.com.BD
Describe forward-biased diode?
A specific amount of current is allowed to flow through a diode. If the current passing through the diode exceeds this specific value, the diode gets heated and is likely to be damaged. Therefore, in the biasing circuit of a resistance which limits the current passing through the diode within its specific value is called Forward biased diode. ANSWER: A forward bias diode is just a diode that it is conducting in the forward direction. Positive to anode and negative to cathode
How are power diode classified?
by reverse breakdown voltage & forward current capacity
What is the behavior of a forward and reverse biased diode?
Forward Resistance:def: It is resistance offered by diode to the forward bias is known as forward resistance.This resistance is not the same for the flow of DC as for the changing current. Accordingly this resistance is of two types :1. DC FORWARD RESISTANCE.2. AC FORWARD RESISTANCE.1. DC forward resistance: It is the opposition by diode to the DC. It is measured by the ratio of DC voltages across the diode to the resulting DC current through it.2. AC forward resistance: It is the opposition offered by the diode to the changing current. It is measured by the ratio of change in voltage across diodes to the resulting change in current through diode. The AC forward resistance is more significant as the diodes are generally used with alternating voltage.Reverse Resistance:def: The resistance offered by the diode to the reverse bias is known as Reverse Resistance. It can be DC reverse resistance or AC reverse resistance depending upon whether the reverse bias is direct or changing voltage. Idealy the reverse resistance of a diode is infinte however in practice the reverse resistance is not infinite because for any value of reverse bias, there does exist a small leakage current. It may be emphasized their that reverse resistance is very large compared to the forward resistance.These Definitions are from PRINCIPLES OF ELECTRONICS by V.K MEHTA and ROHIT MEHTA
What is Meaning of diode rating?
There are two diode ratings. One is the forward current rating, and the other is the reverse breakdown voltage rating. The forward current rating is the maximum current that the diode can conduct before failing, and the reverse breakdown voltage rating is the maximum reverse voltage that can be applied before failing. Of course, the reverse voltage rating has a different meaning in a zener diode, but this answer applies to ordinary diodes.
Explain how a current flows in a semiconducting diode in the two states of biasing?
Let me answer as I've learned. In this case, if the voltage source for forward bias is greater than the voltage source for reverse bias, current will flow in this semiconductive diode. And another way may occur. That is, in case reverse bias voltage is as large as breakdown voltage, reverse breakdown current ,which is because of the minority carrier in p region, will flow and this current can be large to damage the diode. If there is any mistake in my answer, please correct me and I'll thank you for that.
Describe forward bias of a diode?
When the polarity of the battery is such that electrons are allowed to flow through the diode,then the diode is said to be forward-biased. Conversely, when the battery is "backward" and the diode blocks current, then the diode is said to be reverse-biased. A diode may be thought of as like a switch: "closed" when forward-biased and "open" when reverse-biased.
