The current now flowing through the zener diode increases dramatically to the maximum circuit value and once achieved, this reverse saturation current remains fairly constant over a wide range of reverse voltages. The point at which the zener voltage triggers the current to flow through the diode can be very accurately controlled in the doping stage of the diodes semiconductor construction giving the diode a specific zener breakdown voltage , Vz for example, 4.
This zener breakdown voltage on the I-V curve is almost a vertical straight line. From the I-V characteristics curve above, we can see that the zener diode has a region in its reverse bias characteristics of almost a constant negative voltage regardless of the value of the current flowing through the diode. This voltage remains almost constant even with large changes in current providing the zener diodes current remains between the breakdown current I Z min and its maximum current rating I Z max.
This ability of the zener diode to control itself can be used to great effect to regulate or stabilize a voltage source against supply or load variations.
The function of a voltage regulator is to provide a constant output voltage to a load connected in parallel with it in spite of the ripples in the supply voltage or variations in the load current.
A zener diode will continue to regulate its voltage until the diodes holding current falls below the minimum I Z min value in the reverse breakdown region.
Zener Diodes can be used to produce a stabilized voltage output with low ripple under varying load current conditions. By passing a small current through the diode from a voltage source, via a suitable current limiting resistor R S , the zener diode will conduct sufficient current to maintain a voltage drop of Vout. By connecting a simple zener stabilizer circuit as shown below across the output of the rectifier, a more stable output voltage can be produced.
Resistor, R S is connected in series with the zener diode to limit the current flow through the diode with the voltage source, V S being connected across the combination. The stabilized output voltage V out is taken from across the zener diode.
The zener diode is connected with its cathode terminal connected to the positive rail of the DC supply so it is reverse biased and will be operating in its breakdown condition. Resistor R S is selected so to limit the maximum current flowing in the circuit. There is a minimum zener current for which the stabilization of the voltage is effective and the zener current must stay above this value operating under load within its breakdown region at all times. The upper limit of current is of course dependent upon the power rating of the device.
The supply voltage V S must be greater than V Z. One small problem with zener diode stabilizer circuits is that the diode can sometimes generate electrical noise on top of the DC supply as it tries to stabilize the voltage. However, this type of power supply is o What is meant by Zener diode? What is the main function of Zener diode? What is the difference between diode and Zener diode?
What are the advantages of Zener diode? What is Zener diode and types? What is Zener diode made of? How is Zener diode formed? How does Zener diode regulate voltage? Why Zener diode is used in reverse bias? Is Zener diode a rectifier? How do you wire a Zener diode? Is Zener diode energy efficient? What are the important parameters that should know about the Zener diode? Why Zener diode is also called breakdown diode? How do you identify a Zener diode? Why zener diode do not damage after breakdown?
What is the resistance of a Zener diode? Can we use zener diode for rectification purpose? How does zener diode reduce DC voltage? How accurate is a Zener diode? What happens when a zener diode fails? Alliance Semiconductor Co Ametherm Amphenol Aerospace Operat Author: Irene. Date: 13 Jan I z mA MAX. Using Warning Note: Please check their parameters and pin configuration before replacing them in your circuit.
Advantages of Zener Diodes Less expensive than other diodes. Ability to shift voltage. Easily compatible and obtainable across systems. High-performance standard.
Protection from over-voltage. Ability to regulate and stabilize circuit voltage. Greater control overflowing current. Usable in smaller circuits. Minimum Zener Current. Nominal Voltage. Power Dissipation. LM Based NC Adjustable Switching Power Supply Design Mia 14 Oct As we all know, switching regulated power supplies are widely used in electronic equipment due to their small size, lightweight, and high conversion efficiency.
Leave a Reply Cancel reply. Comment Is Empty. Name Needed. Invalid Email Email Needed. Code Needed. Share this on:. Embossed Tape. Reel Size mm. Taping Width mm. Quantity pcs. Taping Code. Power dissipation. At zener breakdown region, a small increase in voltage will rapidly increases the electric current.
Zener breakdown occurs at low reverse voltage whereas avalanche breakdown occurs at high reverse voltage. Zener breakdown occurs in zener diodes because they have very thin depletion region.
Breakdown region is the normal operating region for a zener diode. Zener breakdown occurs in zener diodes with zener voltage Vz less than 6V. The symbol of zener diode is shown in below figure. Zener diode consists of two terminals: cathode and anode. The symbol of zener diode is similar to the normal p-n junction diode, but with bend edges on the vertical bar.
The VI characteristics of a zener diode is shown in the below figure. When forward biased voltage is applied to the zener diode, it works like a normal diode.
However, when reverse biased voltage is applied to the zener diode, it works in different manner. When reverse biased voltage is applied to a zener diode, it allows only a small amount of leakage current until the voltage is less than zener voltage. When reverse biased voltage applied to the zener diode reaches zener voltage, it starts allowing large amount of electric current.
At this point, a small increase in reverse voltage will rapidly increases the electric current. Because of this sudden rise in electric. However, zener diode exhibits a controlled breakdown that does damage the device. The zener breakdown voltage of the zener diode is depends on the amount of doping applied. If the diode is heavily doped, zener breakdown occurs at low reverse voltages. On the other hand, if the diode is lightly doped, the zener breakdown occurs at high reverse voltages.
Zener diodes are available with zener voltages in the range of 1. Power dissipation capacity is very high High accuracy Small size Low cost. It is normally used as voltage reference Zener diodes are used in voltage stabilizers or shunt regulators. Zener diodes are used in switching operations Zener diodes are used in clipping and clamping circuits.
Zener diodes are used in various protection circuits. Open navigation menu. Close suggestions Search Search.
User Settings. Skip carousel. Carousel Previous. Carousel Next. What is Scribd? Explore Ebooks. Bestsellers Editors' Picks All Ebooks. Explore Audiobooks. Bestsellers Editors' Picks All audiobooks. Explore Magazines. Editors' Picks All magazines. Explore Podcasts All podcasts. Difficulty Beginner Intermediate Advanced.
Explore Documents. Uploaded by havejsnj. Did you find this document useful? Is this content inappropriate? Report this Document. Flag for inappropriate content. For Later.
0コメント