The pn junction diode is the basic semiconductor diode format. A pn junction diode is one of the simplest semiconductor devices around, and which has the characteristic of passing current in only one direction only. Bjts, jfets and mesfets, are devices that have more than one pn junction. A key difference is that a pn diode contains two depletion regions of opposite type. Pn junction diode and characteristics of pn junction diode. A pn junction diode is formed with a n type semiconductor and a p type semiconductor and the doping level is normal or moderatethat is the fermi of p type will lie close to the valence band and the fermi of n type will lie c.
If an external dc voltage is given to the circuit in which the semiconductor diode is a part of it, results in a qpoint or operating point on the pn junction diode characteristic curve that does not alter with time. In forward bias condition, current is constant until certain voltage is reached. Power diodes play a significant role in power electronics diode characteristics a power diode is a twoterminal pn junction device. A pn junction diode biased by an external voltage source with a source resistance rs, and a noise equivalent circuit. When anode is positive with respect to the cathode, the diode is said to be forward biased and it conducts. The word diode can be explained as di means two and ode is obtained from electrode. Electrostatic analysis of a pn diode pn juntion diode. The analysis is very similar to that of a metalsemiconductor junction. Pn junction diode applications pn diode applications. The vi characteristics or voltagecurrent characteristics of the pn junction diode is shown in the below figure. Pn and metalsemiconductor junctions the gmu ece department. Voltampere characteristics of pn diode are studied. Pn junction diode characteristics and biasing analyse a meter. Diode is a twoterminal electronic component that conducts electric current in only one direction.
Definition ptype semiconductor is suitably joined to ntype semiconductor,to conduct surface is called pn junction. The contact surface between the layers of ptype and ntype semiconductor pieces plated together so as to form a pn junction is called the pn junction. Pnjunction diode characteristics ppt documentation. Jan 21, 2019 vi characteristics of pn junction diode. These are the easiest and basic diodes available in and use pn junction characteristics like depletion layer, diffusion and drift current. Pn junction diode characteristics electronic circuits and. This potential difference can alter the flow of majority carriers, so that the pn junction can be used as an opportunity for the diffusion of.
Diode characteristics dynamic resistance, transition time. Jubail industrial college jic, analogue electronics, experiment. In addition, they can be used as solar cells, photodiodes, light emitting diodes and even laser diodes. It is also required to obtain the capacitancevoltage characteristics of the diode. Since a junction forms between a p type and n type material it is called as pn junction. Vi characteristics of pn junction diode electronics post. A practical circuit arrangement for a pn junction diode is as shown in the following figure. Najmabadi, ece65, winter 2012 high concentration of h on the p side holes diffuse towards the junction high concentration of e on the n side electrons diffuse towards the junction n side is positively charged because it has lost electrons.
Mar 27, 2019 junction diodes questions and answers q1. The pn junction is the root for semiconductor diodes. From the above, it follows that zero power dissipation occurs in an ideal diode. Semiconductor pnjunction diodes physically, diodes are formed by the interface between two regions of oppositely doped semiconductor i.
Photodetectors, solar cells and leds, are optoelectronic devices that have a pn junction. This is the voltage required to reach a flat band diagram and sets an upper limit typically an overestimate for the voltage that can be applied to a diode before it burns itself up. Jan 29, 2019 pn junction diode is one of the fundamental elements in electronics. May 20, 2016 this pn junction can be used to operate and implement the functions of a diode because it can conduct considerable current in the forward direction and roughly no current in the reverse direction. Image source forward biasing a pn junction diode is very simple. A pn junction diode is a twoterminal electronics element, which can be classified as either. This causes electrons from nregion to get attracted to positive terminal of the battery and holes by the negative terminal. Normally the voltage is taken along the xaxis and current along yaxis. A pn junction is formed by joining ptype and ntype semiconductors together in very close contact. Pn junction diode, characteristics and applications 2020. An ammeter is connected in series and voltmeter in parallel, while the supply is controlled through a variable resistor. A perfect diode is a device that only allows current to flow through it in one direction, i.
Reverse saturation current in a silicon pn junction diode nearly doubles for very a. This potential difference can alter the flow of majority carriers, so that the pn junction can be used as an opportunity for the diffusion of electrons and holes. Working of pn junction diode with biasing, characteristics. Zero bias no external voltage potential is applied to the pn junction diode. On the other hand, when the source resistance rs is much larger than the di. Static resistance or dc resistance of a pn junction diode defines the diodes resistive nature when a dc source is connected to it. Because of its electrical properties, silicon is called a semiconductor. Semiconductor physics semiconductors and diodessemiconductors. A pn junction diode is formed when a ptype semiconductor is fused to an ntype semiconductor creating a potential barrier voltage across the diode junction the effect described in the previous tutorial is achieved without any external voltage being applied to the actual pn junction resulting in the junction being in a state of equilibrium. The pn junction biasing the pn junction the diode trouble shooting. The pn junction diode provides characteristics that are used in rectifiers and switching circuits and will also be applied to other devices. The diode has two terminals called a cathode and an anode.
As shown in the figure, pn junction diode is a 2 terminal polarity sensitive device. This pn junction can be used to operate and implement the functions of a diode because it can conduct considerable current in the forward direction and roughly no current in the reverse direction. The pnjunction diode is mainly used for rectification purpose, whereas the zener diode is used for providing the. Iv characteristics to model foward bias region we need 2 new concepts the law of the junction steady state diffusion 0 0. Pn junction diode applications physics and radioelectronics. Once the applied bias voltage is increased to a value where the reverse voltage across the diode reaches the breakdown value of the diode which is vbr, the reverse current begins to increase rapidly.
It is the most essential and the basic building block of the electronic device. Pn junction diode and diode characteristics electronicstutorials. This page of application notes section covers pn junction diode applications. The term junction refers to the boundary interface where the two regions of the semiconductor meet. Characteristics of junction diodes technical articles. A pn junction has rectifying currentvoltage iv or iv characteristics as shown in fig. If we join a piece of p type material to a pieceof n type material such that the crystalstructure remains continuous at the boundary, a pn junction is formed 2. There are many different applications with pn junctions. If the negative terminal of the battery is connected to the ptype semiconductor and the positive terminal of the battery is connected to the ntype semiconductor, the diode is said to be in reverse bias. This is the voltage across the diode at which it starts conducting. In this article, we will focus on the iv characteristics of the junction diode, specifically the pn junction. Calculate the resistance in forward bias and reverse bias. Silicon a single silicon atom consists of fourteen negatively. Octavian florescu 2 the pn junction diode schematic diagram ptype ntype id.
When a reverse bias is applied across a pn junction diode, there is an extremely small reverse current ir through the pn junction due to minority carriers. Pn junction diode in the reversebiased configuration is sensitive to light from a range between 400nm to nm, which includes visible light. By exploring the electrical properties of silicon, it is possible to acquire an understanding of the inner workings of the pn junction. The pnjunction is the root for semiconductor diodes. Apr 05, 2019 working of pn junction diode if an external potential is applied to the terminals of pn junction, it will alter the potential between the p and nregions. Last, but not least, the pn junction and its characteristics are the basis of almost every semiconductor device made. The pn junction has the very useful property that electrons are only able to flow in one direction.
Pn junction diode acts as a rectifier as seen in the iv characteristic. When the diode is forwardbiased, it can be used in led lighting applications. Pn junction diode is one of the fundamental elements in electronics. Us9006858b2 highvoltage trench junction barrier schottky. Pn junction diode applications a pn junction diode is a two terminal device that allows electric current in one direction and blocks electric current in another direction. Voltampere vi characteristics of a pn junction or semiconductor diode is the curve between voltage across the junction and the current through the circuit. The pn junction diode is a twoterminal device, which is formed when one side of the pn junction diode is made with ptype and doped with the ntype material. Pn junction diode v i characteristics of pn junction diode. The junction diode basic operation the diode is fabricated of a semiconductor material, usually silicon, which is doped with two impurities.
However, there is a uctuation in the junction voltage v due to the slow relaxation time crs of. It is used in the construction of transistors, fet, gates and many other types of integrated circuits. Jan, 2015 pn junction diode characteristics lab expriment 1. It is used for many forms of rectification for current levels both large and small, as well as high and low voltage levels, and it finds many uses in all manner of electronic circuits. When diode conducts it has a small forward drop voltage which depends on manufacturing process and. Forward bias current flows reverse bias no current flow.
Apr 29, 2019 static resistance or dc resistance of a pn junction diode defines the diodes resistive nature when a dc source is connected to it. The pn junction is the fundamental building block of the electronic age. Working of pn junction diode if an external potential is applied to the terminals of pn junction, it will alter the potential between the p and nregions. In vi characteristics of pn junction diode is two operating regions and three possible biasing conditions for the standard junction diode and these are. Semiconductor, silicon, pn junction, forward bias, reverse bias, diode. Lecture 16 the pn junction diode ii equivalent circuit model november 3, 2005 contents. You just need to take a battery whose values can be varied from o to v volts, connect its positive terminal to the pside of pn junction diode and then connect the negative terminal of battery to the nside of the pn junction diode. Semiconductor pn junction diodes physically, diodes are formed by the interface between two regions of oppositely doped semiconductor i. Pn junction diode junction diode symbol and static iv characteristics. P type and n type semiconductors, takenseparately are of very limited use.
Pn junction diode baising and its vi characteristics. Now, if we join the two types of semiconductors ptype and ntype together then a new device is formed called as pn junction diode. There are two operating regions and three possible biasing conditions for the standard junction diode and these are. Iv characteristics pn junction diode reverse biasing a pn junction when the polarity of the battery is reversed, the cathode is connected to positive end of the battery and anode to negative. The pn junction supports unidirectional current flow. In this type of diode, we dope one side of a semiconductor piece with an acceptor impurity and another side with a donor impurity. This time consists of a transient and an interval of time before the diode attains a steady state. Lecture 15 the pn junction diode i iv characteristics november. The pn junction is a versatile element, which can be used as a rectifier, as an isolation structure and as a voltagedependent capacitor.
We prefer to read our article on pn junction first before reading this guide for maximum understanding. Pnjunction diode and diode circuits 1 main properties of semiconductors 2 the pnjunction in equilibrium 3 the i v characteristics of the pnjunction 4 deviations from the ideal diode 5 analysis of the diode circuits 6 rectifier circuits. The pnjunction obey the ohms law whereas zener diode does not obey the ohms law. One side is doped with a donor or ntype impurity which releases electrons into the semiconductor lattice. What is the difference between pn junction diode and tunnel. The barrier increase reduces the majority carrier diffusion to a negligible level.
Pn junction diodes as the name suggests are diodes made up by combining one p type and one n type semiconductor. Junction diodes questions and answers electronics post. The ohms law said that the voltage applies across the diode is equal to the product of the current and resistance applied across the diodes. These electrons are not bound and are free to move about. The electrostatics of the pn junction is considered in this chapter and the currentvoltage characteristics of the pn junction diode are developed in the next chapter. Note to those familiar with a diode turn on voltage. The horizontal line in the below figure represents the amount of voltage applied across the pn junction diode whereas the vertical line represents the amount of current flows in the pn junction diode. Electrostatic analysis of a pn diode pnjuntiondiode. A pn junction with open terminals excluding minority carriers f. Vi characteristics of pn junction diode in 3biasing modes. This pn diode applications are very useful for beginners.