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. A pn junction diode is a twoterminal electronics element, which can be classified as either step graded or linear graded. It is acting as normal diode while forward biasing. Pn junction theory a pnjunction is formed when an ntype material is fused together with a ptype material creating a semiconductor diode in the previous tutorial we saw how to make an ntype semiconductor material by doping a silicon atom with small amounts of antimony and also how to make a ptype semiconductor material by doping another. A typical vi characteristic for a forward biased pn junction is shown in the figure below.
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. Characteristics of junction diodes technical articles. Pn junction is formed by bringing a p type material in contact with n type material. 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. Depletion region created across the pn junction by the initial movement of majority carrier across the junction. Pn junction diode is one of the fundamental elements in electronics. Voltampere characteristics of diode in forward bias condition. Pn junction diode baising and its vi characteristics elprocus. The characteristics near the origin of the graph are virtually symmetrical. Apr 23, 2018 semiconductor pn junction diode is the simplest semiconductor device. The lead connected to the ptype material is called the anode and the lead connected to the ntype material is the cathode. P type and n type semiconductors, takenseparately are of very limited use. An ideal pn junction diode does not conduct in reverse biased condition. In general, the cathode of a diode is marked by a solid line on the diode.
There are three biasing conditions for pn junction diode and this is based on the voltage applied. In this type of diode, we dope one side of a semiconductor piece with an acceptor impurity and another side with a donor impurity. In zener diode, electric current flows from both anode to cathode and cathode to anode. 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. This article gives a brief information about the pn junction diode, pn junction diode in forward bias and reverse bias and the vi characteristics of pn junction diode. The arrow indicates the flow of current through it when the diode is in forward biased mode, the dash or the block at the tip of the arrow indicates the blockage of current from the opposite direction. Jun 12, 2016 voltage vs current characteristics of pn junction, simulation done with the help of national instruments software like ni multisim is used. These diodes operate at a precise value of voltage called break down voltage. Pn junction diode characteristics electronic circuits and. In forward bias negative terminal is connected to ntype material and the positive terminal is connected to ptype material across the diode shows the decrease in the builtin potential barrier. In a schottky barrier diode current conduction is through majority carriers which are electrons in n type semiconductor. It has a particular voltage known as break down voltage, at which the diode break downs while reverse biased.
Pn junction diode and characteristics of pn junction diode. The tunnel diode was first introduced by leo esaki in 1958. What are the characteristics of a pn junction diode. Basics of led light emitting diode as mentioned in the introduction, an led is a semiconductor light source. Plot a graph with reverse voltage along x axis and reverse current along y axis. Jan 21, 2019 v i characteristics of pn junction diode. However, at ordinary room temperature, a potential difference of about 0. Tunnel diode basics, operation, vi characteristics. Depletion layer opposes only the the majority carrier not minority carrier. Schottky barrier diodeconstructionvi characteristics. The vi characteristics of schottky barrier diode is steeper compared to vi characteristics of normal pn junction diode due to high concentration of current carriers. Dec 16, 2017 a tunnel diode is a special type of pn junction diode that shows the negative resistance between two values of forward voltage ie, between peak point voltage and valley point voltage.
Normally the voltage is taken along the xaxis and current along yaxis. A pn junction diode is a two terminal single crystal semiconductor device whose one side is doped with acceptors and other side by donors. The pn junction barrier is formed during the process of manufacturing itself compared to germanium silicon has the highest barrier potential. We have seen how a diode is made with p and n semiconductors but. Semiconductor pn junction diode working pn diode vi. In this article, we will focus on the iv characteristics of the junction diode, specifically the pn junction. In the case of normal diodes the diode damages at the break down voltage.
However, unlike a resistor, a diode does not behave linearly with respect to the applied voltage as the diode has an exponential currentvoltage iv relationship. The behaviour of a diode in a circuit is given by its iv characteristics. Pn junction diode junction diode symbol and static iv characteristics. When the ntype semiconductor and ptype semiconductor materials are first joined together a very large density gradient exists between both sides of the pn junction. The graph shows the reverse v i characteristics of the given pn junction diode. Pn junction diode and its biasing junction field effect transistor. A tunnel diode is a special type of pn junction diode that shows the negative resistance between two values of forward voltage ie, between peak point voltage and valley point voltage. The full explanation of biasing a diode is given below with vi characteristics of pn junction diode. Aug 14, 2019 the above are some of the basics of the pn junction diode and this article covers about the vi characteristics of the pn junction diode. Pn junction theory charge representation, ptype, ntype. 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. Electronics tutorial about the pn junction diode and the vi characteristics of pn junction diode when used as a diode rectifier. This potential is highly sensitive to the variations in the temperature, the element or material utilized in its fabrication as well as the concentration of doping required based on the type and the factors.
Vi characteristics of pn junction diode electronics post. The characteristic curve for the tunnel diode is made up from several different elements normal diode current. Zero bias no external voltage potential is applied to the pn junction diode. Both silicon and germanium can be combined with other elements called dopants to create solidstate electronic devices, such as diodes, transistors and photoelectric cells. A zener diode conducts excellently even in reverse biased condition. The pn junction has the very useful property that electrons are only able to flow in one direction. Dec 27, 2017 the symbolic representation of the diode is as follows. The symbolic representation of the diode is as follows. The symbol of zener diode is similar to the normal pn junction diode, but with bend edges on the vertical bar.
To get vi characteristics, the currents corresponding to varying input voltages are noted and vi graph is observed in the output graph. The main function of the semiconductor diode is, it facilitates the electrons to flow totally in one direction across it. There are two operating regions and three possible biasing conditions for the standard junction diode and these are. The above are some of the basics of the pn junction diode and this article covers about the vi characteristics of the pn junction diode. The vi characteristics of pn junction diode in forwarding bias are nonlinear, that is, not a straight line. 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. A pn junction is a boundary or interface between two types of semiconductor materials, ptype and ntype, inside a single crystal of semiconductor. It is seen that the forward current rises exponentially with the applied forward 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. Read more pn junction diode and its working principle. This causes electrons from nregion to get attracted to positive terminal of the battery and holes by the negative terminal. The basic diode symbol and static vi characteristics. Jun 17, 2018 using v i characteristics of the diode, it is easy to find the voltage and current in the circuit which contains the diode.
Silicon and germanium are two chemical elements called metalloids. The pn junction diode is the basic semiconductor diode format. Zener diode is a pn junction diode specially designed to operate in the reverse biased mode. Simulator procedure as performed through the online labs select the characteristics of diode from the drop down list. Using vi characteristics of the diode, it is easy to find the voltage and current in the circuit which contains the diode. The graph shows the reverse vi characteristics of the given pn junction diode. Voltage vs current characteristics of pn junction, simulation done with the help of national instruments software like ni multisim is used. Pn junction diode and diode characteristics electronicstutorials. In a schottky barrier diode current conduction is through majority carriers which are electrons in. A zener diode when forward biased behaves like an ordinary pn junction diode. In this video, we will discuss the vi characteristics of pn junction. It is the most essential and the basic building block of the electronic device. A pnjunction 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. 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.
Semiconductor pn junction diode is the simplest semiconductor device. The primary difference between silicon and germanium diodes is the voltage needed for the diode to turn on. The vi characteristics or voltagecurrent characteristics of the pn junction diode is shown in the below figure. When a diode is forward biased and conducts a forward current i f flows through it which causes a voltage drop i f r f in the forward resistance. It is one of the simplest semiconductor devices as. May 25, 2019 the pn junction barrier is formed during the process of manufacturing itself compared to germanium silicon has the highest barrier potential. 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.
Nov 02, 2017 basics of led light emitting diode as mentioned in the introduction, an led is a semiconductor light source. A diode allow electric current to pass in forward direction and block current in reverse direction. Hence, the forward voltage v f applied across the real diode for. Pn junction diode characteristics explained in detail. 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. Voltampere vi characteristics of a pn junction or semiconductor diode is the curve between voltage across the junction and the current.
This is the basic construction of the pn junction diode. 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. A perfect diode is a device that only allows current to flow through it in one direction, i. 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. A very quick way to look at the behaviour of an electronic device is to look at its characteristics. Simulator procedure as performed through the online labs select the characteristics of diode from the. A pn junction diode is formed by doping one side of a piece of silicon with a ptype dopant boran and the other side with a ntype dopant phosphorus. Pn junction diode vi characteristics in forward and reverse bias. Note to those familiar with a diode turn on voltage. Jul, 2016 the vi characteristics may be obtained by performed dc sweep analysis. The potential developed across the junction due to the influence of the carriers is termed as diffusion voltage. It consists of a pn junction diode and when voltage is applied to the led, electrons and holes recombine in the pn junction and release energy in the form of light photons.
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. The diode has two terminals called a cathode and an anode. Voltampere vi characteristics of a pn junction or semiconductor diode is the curve between voltage across the junction and the current through the circuit. This is the normal or expected current that would flow through a pn junction diode. The v i characteristics or voltagecurrent characteristics of the pn junction diode is shown in the below figure. Doping with acceptor creates p type semiconductor while doping with donors produces n type. This article discusses about pn junction diode, diode theory of zero bias, forward bias, reverse bias with vi characteristics and its applications. Pn junction theory a pn junction is formed when an ntype material is fused together with a ptype material creating a semiconductor diode in the previous tutorial we saw how to make an ntype semiconductor material by doping a silicon atom with small amounts of antimony and also how to make a ptype semiconductor material by doping another. The p positive side contains an excess of holes, while the n negative side contains an excess of electrons in. The pn junction diode is appeared in the year 1950. Image source forward biasing a pn junction diode is very simple.
The vi characteristics may be obtained by performed dc sweep analysis. Voltampere v i characteristics of a pn junction or semiconductor diode is the curve between voltage across the junction and the current through the circuit. 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. Pn junction diode, its characteristics and applications. Pn junction diode theory and vi characteristics of pn. Vi characteristics of pn junction diode topics covered. Pn junction diode baising and its vi characteristics. The pn junction diode is a two terminal 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 theory and vi characteristics of pn junction diode. Its characteristics are completely different from the pn junction diode. A semiconductor diode is the most common type diode, which is a piece of semiconductor material with a pn junction connected to two terminals. Working of pn junction diode with biasing, characteristics. One terminal of pn junction diode is anode and other is cathode.
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