A zener diode is a semiconductor device which conducts in forward biased as well as reversed biased. Difference between diode and rectifier difference between. The 500mw, bzx55 series zener diodes are generally available in the range varying from 2. When the voltage across the terminals is reversed and the potential reaches the zener voltage or knee, the junction will break down and current will flow in the reverse direction a desired characteristic. Difference between diode, zener diode, and schottky diode.
Diode can conduct current only in one direction, whereas zener diode allows the conduction in both directions. The other differences between the pnjunction and zener diode are shown in the comparison chart. Thus, a normal pn junction diode is considered as a unidirectional device. Recipe for solving diode circuits state of diode is unknown before solving the circuit 1. Difference between zener diode and normal rectifier diode. Zener diode is on when it operates on the zener region, i. A zener diode is a type of diode that allows current to flow in the conventional manner from its anode to its cathode i. A zener diode is a special kind of diode which allows current to flow in the forward direction in the same manner as an ideal diode, but will also permit it to flow in the reverse direction when the voltage is above a certain value known as the breakdown voltage, zener knee voltage or zener voltage. If this reverse biased voltage across the diode is increased continually, the depletion layer becomes more and more wider. A small amount of current is also produced when no light is present. These characteristics let zener diodes have a definite reversebreakdown voltage. The relationship is obtained by applying kvl and it is vs vg r im. At the same time, there will be a constant reverse saturation current due to minority carriers after certain reverse voltage across the junction, the.
Zener diode working, characteristics and application as. For normally doped pn diode, depletion region is thick. By using an led and a zener diode we can create a circuit which gives turns on. This is the voltage at which the diodes begins to conduct current in the reverse direction, and its one difference between zener diode and rectifier diode setups. A zener diode is a special type of device designed to operate in the zener breakdown region. Zener diode is a special kind of diode which permits the flow of current in the forward direction as well as in reverse direction when the voltage is above a certain voltage known as breakdown or zener voltage. It consists of an ntype semiconductor and a ptype semiconductor that are placed together. These diodes have a defined voltage drop that doesnt change much over a range of input voltages. The other differences between the diode and led are shown below in the comparison chart. A characteristic zener diode for general purpose electronic circuits has the power rating of 500mw, bzx55 zener diode series or the larger 1.
But since there are so many types of a diode, how to differentiate between them and most importantly which one to use according to its requirement in our circuit. They can also be used in other circuits apart from just providing a voltage reference. Zener effect and avalanche effect electrical engineering. A normal diode if operated in reversed biased will get destroyed. Difference between pn junction diode and zener diode. Zener diode symbol zener diode circuit zener diode vi characteristics zener diode working zener diode applications faqs. Zener diode as voltage regulator and its vi characteristics. Again, in this lab, there were two di erent kinds of power supplies built. When a pn junction diode is reverse biased, the depletion layer becomes wider. Zener diode definition a zener diode is a type of diode that permits current to flow in the forward direction like a normal diode, but also in the reverse direction if the voltage is larger than the breakdown voltage known as zener knee voltage or zener voltage. The doping intensity is also one of the key features which distinguish conventional diode and zener diode.
The normal pn junction diode is moderately doped while the zener diode is doped properly in such a way that it possesses sharp breakdown voltage we will discuss some other differences between diode and zener diode with the help of comparison chart. Zener diodes when we first talked about practical diodes, it was mentioned that a parameter associated with the diode in the reverse bias region was the breakdown voltage, v br, also known as the peakinverse voltage piv. Difference between diode and zener diode with comparison. Before jumping to its type or difference between diode, zener diode, and schottky diode, lets see some basic specifications of a diode first. There are several types of diodes available, with the most common type of diode being the semiconductor diode, which is present almost in any electrical circuit that you may look at.
Difference between diode and zener diode compare the. A diode is a type of electrical device that only allows current to move through it in one direction. The zener diode is fabricated from the element silicon. Difference between zener diode and normal rectifier diode a diode is a passive device which allows the flow of current in one direction only. What is the difference between rectifiersignal diode and. Difference between diode and zener diode diode vs zener. Diode is an electronic component that allows the flow of electricity in one direction without resistance or with very little resistance while in the opposite direction has. The current is generated when photons are absorbed in the photodiode. A diode is a semiconductor device which conducts in one direction only. Diffusion current free electrons from the ntype material combine with the holes in. A diode can be defined as the fundamental electronic component that allows the flow of electricity in one direction only.
Electronics tutorial about the zener diode and how the zener diode can be used with a. There are two entirely different effects exploited in zener diodes. When forward biased voltage is applied to the zener diode it allows large amount of electric current and blocks only a. On the contrary, zener diode is designed in a way that it can conduct in a. Electrons diffuse across the junction and combine with majority holes. V z zener voltage v z is the reverse voltage at which breakdown occurs in a zener diode.
In such a diode for reverse bias in excess of 6v, the breakdown is through process of avalanche multiplication or secondary emission. Since the zener diode is at the zener voltage in the reverse bias direction. A zener diode is a type of diode that permits current to flow in the forward direction like a normal diode, but also in the reverse direction if the voltage is larger not equal to, but larger than the rated breakdown voltage known as zener knee voltage or zener voltage. Zener diodes acts like normal pn junction diodes under forward biased condition. A zener diode is pretty much like any other diode, except its reverse breakdown voltage that is, the reverse voltage above which it abruptly starts conducting lots and lots of current is tightly controlled, making it usable as a crude sort of voltage regulator. This is because when the reverse voltage applied across the zener diode. On the other hand an ic voltage regulator draws from power source a bias current which is almost constant regardless of the load and input voltage and in most cases is. What is the difference between a diode, a zener diode, and. Amount of doping for p and n semiconductor layers are different in the two devices. A zener diode is a heavily doped diode with a very narrow depletion region.
In this article, we are going to explain zener diode and its applications in detail. Diode is an electronic component that allows the flow of electricity in one direction without resistance or with very little resistance while in the opposite direction has an infinite or at least very high resistance. Zener diode as voltage regulator tutorial electronicstutorials. Diode applicationszener diode zener diode zener diode operates in reverse bias rb at the zener voltage v z. User may specify either, both, or neither of the at least and no more than values. How are zener diodes different to silicon pn diodes.
Power is calculated by multiplying current by voltage pie, so we can calculate power dissipations for both the resistor and the zener diode quite easily. Basics currentvoltage characteristic of a zener diode with a breakdown voltage of 17 volt. Zener diodes or voltage reference diodes are used in a variety of circuits to enable them to provide a voltage reference. The active portion of a zener diode is a semiconductor pn junction. A normal diode will be permanently damaged for a large reverse current, but a zener diode will not. There are many circuits that use zener diodes, ranging from very simple zener diode circuits, up to far more complicated ones. This was a bad thing before the whole avalanche breakdown, large current. Thus in a reverse biased diode, a thermally generated carrier falls down the junction barrier and acquire energy from the applied.
A diode is a device used in electricity to allow a current to move in only one direction easily. A zener diode is a silicon semiconductor device that permits current to flow in either a forward or reverse direction. For example, a dc motor can produce a surge voltage because it continues to. It permits the flow of current in the forward direction and also in the reverse direction. Write down all circuit equations and simplify as much as possible 2. The voltage specification of a zener diode is its breakdown voltage, this is the voltage that the zener will pass. A zener diode is a special type of rectifying diode that can. In our previous articles, we explain in detail about diodes, pn junction diode, semiconductors etc.
1282 364 646 654 181 65 841 1276 1177 86 1518 901 584 826 88 1451 658 135 1228 135 389 477 517 51 1031 1227 1492 971 979 695 101 295 603 712 1278 712 513 991 804 1397