Pn junction diode characteristics explained in detail. The vi characteristics of a diode can be forward or reverse. It is used majorly in rectifier and voltage regulator circuits. We have also learned about diffusion current, depletion region, drift current and barrier potential.
Definition ptype semiconductor is suitably joined to ntype semiconductor,to conduct surface is called pn junction. This was conducted as an introductory to electronics laboratory and in line with some topics in lecture classes. Increase the current in small steps and note down the corresponding junction voltage. Now, if we join the two types of semiconductors ptype and ntype together then a new device is formed called as pn junction diode. This causes electrons from nregion to get attracted to positive terminal of the battery and holes by the negative terminal. Silicon a single silicon atom consists of fourteen negatively. Static resistance or dc resistance of a pn junction diode defines the diodes resistive nature when a dc source is connected to it. The pnjunction is the root for semiconductor diodes. The analysis is very similar to that of a metalsemiconductor junction.
There are two operating regions and three possible biasing conditions for the standard junction diode and these are. To plot forward and reverse characteristics of given pn junction diode. Objective the objective of this experiment is to measure the iv curve for pn junction diode and to understand the characteristics of pn junction. In forward bias condition, current is constant until certain voltage is reached.
We use zener diodes for voltage regulation and voltage stabilisation. Figure 1 at the junction initially free charge carriers. If you find these terms foreign, just read the chapter about. Pn junction diode characteristics vi forward and reverse pn junction diode is a semiconductor devices which conducts from only one side. Since a junction forms between a p type and n type material it is called as pn junction. The zener breakdown voltage is the minimum reverse biased voltage below which the diode blocks the reverse. The zener diode mainly operates in reverse biased condition.
Other semiconductor components are made from more complicated arrangements. By exploring the electrical properties of silicon, it is possible to acquire an understanding of the inner workings of the pn junction. Working of pn junction diode with biasing, characteristics. Calculate lniand plot a graph between lniand junction voltage, v. Conclusion this experiment focuses on the investigation of. The graph shows the reverse vi characteristics of the given pn junction diode. Thus the forward and reverse characteristics of pn junction diode was plotted and their corresponding static and dynamic resistance was found. As the name stands pn junction diode is made up of p type and n type semiconductor material. A junction diode is formed when a ptype semiconductor is in intimate contact with ntype semiconductor. Pn junction diode vi characteristics in forward and. Pdf electrical characterization of a pn junction diode. Diode characteristics physics astronomy project topics. Pn junction diode junction diode symbol and static iv characteristics. The critical parameter of this type of diodes is the zener breakdown voltage.
Dont feel bad if you havent studied pn junctions before. For the forward characteristics of the given pn junction diode, a graph is plotted with forward voltage along x axis and forward current along y axis. It is also required to obtain the capacitancevoltage characteristics of the diode. When pn junction diode in forward bias it conducts and allow the current through it like on switch, when pn junction diode in reverse bias it does not conducts like off switch. The lead connected to the ptype material is called the anode and the lead connected to the ntype material is the cathode. The word diode can be explained as di means two and ode is obtained from electrode. Plot a graph with reverse voltage along x axis and reverse current along y axis.
Forward bias current flows reverse bias no current flow. Pdf experiment on the physics of pn junction giacomo. Diode characteristics dynamic resistance, transition time. Semiconductor, silicon, pn junction, forward bias, reverse bias, diode.
Characteristics of junction diodes technical articles. Simulator procedure as performed through the online labs select the characteristics of diode from the. 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. 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. They provide a lowcost and no frill method for voltage regulation. The forward and reverse characteristics of the given pn junction diode is drawn. Most of the commercial leds are realized using a highly doped n and a p junction. 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. To study and verify the functionality of a pn junction diode in forward bias b pointcontact diode in reverse bias components equipments required. The pn junction is the fundamental building block of the electronic age. While doing the experiment do not exceed the ratings of the diode.
When carriers are injected across a forwardbiased junction, it emits incoherent light. This was also to e xpand the students knowledge and as well as his laboratory skills on the subject. Conclusion this experiment focuses on the investigation of the basic characteristics of a diode. An isolated pn junction makes a semiconductor diode.
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. From the experiment, the following conclusions were drawn. It is the ratio of change in voltage to change in current from vi characteristics of the diode. A semiconductor diode is prepared by joining p and n sections of a semi conducting.
Lab experiment related theory available in following books. To plot voltampere characteristics of silicon pn junction diode. Diodes and diode circuits tlt8016 basic analog circuits 20052006 2 3. A pn junction is said to be forward biased when pregion is connected to positive terminal and n. 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.
Connect the diode to the pnjunction setup as shown in the figure 1. A very small current will made at the junction due to the movement of minority charge carriers across the junction. A pn junction diode is a twoterminal electronics element, which can be classified as either step graded or linear graded. Vi characteristics of pn junction diode in 3biasing modes. Pn junction diode and its characteristics in chapter 1 understanding the pn junction, we have seen how a pn junction is formed from a ptype and ntype semiconductor. A key difference is that a pn diode contains two depletion regions of opposite type. A light emitting diode led is essentially a pn junction diode. Pn junction diode and diode characteristics electronicstutorials. The potential developed across the junction due to the influence of the carriers is termed as diffusion voltage. Pn junction diode and characteristics of pn junction diode.
It is the most essential and the basic building block of the electronic device. Observation of characteristics of a zener diode debangshu mukherjee bs. The forward current shows a sudden increase at certain forward voltage, which is known as the knee voltage. Pn junction diode characteristics and working elexfocus.
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. The semiconductor diode is formed by doping ptype impurity in one side and ntype of impurity in another side of the semiconductor crystal forming a pn junction as shown in the following figure. Experiment 16 the pn junction introduction in this experiment on the physics of the pn junction, a determination is made of both the universal constant ek i. This same diode and its characteristics are shown in figure 1. Imagine a pn junction with metallic contacts at both the ends for application of external voltage. In this article, the forward and reverse biases characteristics of a pn junction diode using a keithley 2400 source measure unit were measured and the important parameters of diode such as.
P type and n type semiconductors, takenseparately are of very limited use. 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. It generally shows the relation between bias voltage and current of a diode. Electrostatic analysis of a pn diode pnjuntiondiode. Lecture 15 the pn junction diode i mit opencourseware. In this article, we will focus on the iv characteristics of the junction diode, specifically the pn junction. The barrier increase reduces the majority carrier diffusion to a negligible level. This threshold voltage concept comes from the fact that a diode is just a pn junction. This is the symbolical representation of a semiconductor diode in the image above, the arrow indicates the direction of current when the diode is under forward bias. Experiment 1 vi characteristics of diode 1 vi characteristics of diode aim. To find cut in voltage for silicon pn junction diode. The purpose of this laboratory investigation is to determine the voltage and current characteristics of several pn junction diodes including the 1n4148 signal diode, the 1n4004 rectifier diode and the 1n5231b zener diode.
Pn junction diode is one of the fundamental elements in electronics. To find cutin voltage for silicon pn junction diode. To study the forward and reverse bias characteristics of diode and zener diode. 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 general, the cathode of a diode is marked by a solid line on the diode. 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. The pn junction biasing the pn junction the diode trouble shooting. To study the characteristics of pn junction diode under a forward bias. 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 above are some of the basics of the pn junction diode and this article covers about the vi characteristics of the pn junction diode. To study and verify the functionality of a pn junction diode in forward bias b pointcontact diode in reverse. Conduct the experiment for obtaining the forward bias vi characteristics of the given diode. It is also important to note here that the equilibrium barrier potential can be altered. Experimently find out whether the given diode is made of germanium or silicon.
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