This was conducted as an introductory to electronics laboratory and in line with some topics in lecture classes. By exploring the electrical properties of silicon, it is possible to acquire an understanding of the inner workings of the pn junction. When carriers are injected across a forwardbiased junction, it emits incoherent light. We now consider a pn diode with an applied bias voltage, va. The load resistance r l is connected to these terminals through a pn junction diode d. This lecture uncovers the basic science of semiconductor devices and solar cells, including pn junction and photovoltaic effects.
Pdf experiment on the physics of pn junction giacomo. Energy band gap apparatus containing micrometer, voltmeter, temperature controlled electric oven to heat up the diode, pn junction. The pnjunction is the root for semiconductor diodes. Working of pn junction diode with biasing, characteristics. Connect the diode to the pnjunction setup as shown in the figure 1. Increase the current in small steps and note down the corresponding junction voltage. Conclusion this experiment focuses on the investigation of. The graph shows the reverse vi characteristics of the given pn junction diode. To draw the characteristic curve of a zener diode and to determine its reverse break down voltage. Most of the commercial leds are realized using a highly doped n and a p junction. Lecture 15 the pn junction diode i iv characteristics november 1, 2005 contents. Jan 02, 2019 we are going to learn about an experiment to find out the zener breakdown voltage and draw the characteristics of zener diode. 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.
To plot voltampere characteristics of silicon pn junction diode. Pn junction diode experiment using breadboard and simple components duration. A pn junction is the metallurgical boundary between the n and pregions of a semiconductor crystal. This experiment proved that diode controls the direction of the current. Conclusion this experiment focuses on the investigation of the basic characteristics of a 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. A light emitting diode led is essentially a pn junction diode. The following task will acquaints us with the characteristics of a nonlinear devise the diode. The vi characteristic of zener diode indicates that characteristic of zener diode in forward bias is same as pn junction diode. They are also called pn diodes in analogy with vacuum diodes. For the analysis of the accumulated data we shall use a spreadsheet.
Connect the circuit as shown in figure 1 using silicon pn junction diode. Pn junction diode baising and its vi characteristics. But if the reverse bias is increased, at a particular voltage it starts conducting heavily. The pn junction is a versatile element, which can be used as a.
Name quantity name quantity 1 diode by127, oa79 1one no each dc regulated power supply. The principle of operation will be explained using a gedanken experiment, an experiment, which is in principle possible but not necessarily executable in practice. In reverse bias, a negligible constant current flow through the zener diode but the current becomes abruptly large at certain voltage. Temperature dependence of the saturation current of a junction diode scope the determination of the temperature dependence of the saturation current in reverse biased pn junction diodes silicon and germanium in order to determine the dominant contribution to the saturation current. It acts as a diode, which can serve in electronics as a rectifier, logic gate, voltage regulator zener diode, switching or tuner varactor diode. The objective of this experiment is to measure the iv curve for pn junction diode and to understand the characteristics of pn junction. Why is silicon preferred over germanium in the manufacture of semiconductor devices.
A pn junction diode is formed when a single crystal of semiconductor is doped with acceptors impurities pentavalent on one side and donor impurities trivalent on the other side. A pn junction diode is formed by joining together ntype and ptype silicon. A pn junction diode is made by forming a ptype region of material directly next to a ntype region. Semiconductor physics semiconductors and diodessemiconductors. Silicon a single silicon atom consists of fourteen negatively.
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. We use zener diodes for voltage regulation and voltage stabilisation. This causes electrons from nregion to get attracted to positive terminal of the battery and holes by the negative terminal. Calculate lniand plot a graph between lniand junction voltage, v. An isolated pn junction makes a semiconductor diode. Semiconductor, silicon, pn junction, forward bias, reverse bias, diode. Reverse bias the diode with voltage from 1v to 5v with 1v step and measure the capacitance the reversebiased pn junction. The pn junction biasing the pn junction the diode trouble shooting. In forward bias condition, current is constant until certain voltage is reached. Oct 22, 2016 pn junction diode experiment using breadboard and simple components duration.
A pn junction is said to be forward biased when pregion is connected to positive terminal and nregion to the negative terminal of battery. The current through an ideal pn junction is given by the diode equation. In forwardbiased, the led turned on because the voltage of the power source overcame the. Now lets try applying an external voltage to the pn junction diode. A pn junction diode is a twoterminal electronics element, which can be classified as either step graded or linear graded. The pn junction is the root for semiconductor diodes. Forward bias current flows reverse bias no current flow. The conversion of alternating current into direct current is known as rectification. 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. Engineering physics lab phy102 when the polarity of the battery is such that electrons are allowed to flow through the diode. Other semiconductor components are made from more complicated arrangements.
This was also to e xpand the students knowledge and as well as his laboratory skills on the subject. Diode a diode is a 2 lead semiconductor that acts as a one way gate to electron flow. It is the most essential and the basic building block of the electronic device. Lecture 15 the pn junction diode i mit opencourseware. Pn junction diode and diode characteristics electronicstutorials. Zener breakdown voltage should be approximately close to the desired voltage.
The potential at terminal x with respect to y will vary as a sine function with time. A pn junction is said to be forward biased when pregion is connected to positive terminal and n. Pn junctions consist of two semiconductor regions of opposite type. The pn junction supports unidirectional current flow.
From the experiment, the following conclusions were drawn. The zener diode mainly operates in reverse biased condition. Pn junction diode in the reversebiased configuration is sensitive to light from a range between 400nm to nm, which includes visible light. Thus the forward and reverse characteristics of pn junction diode was plotted and their corresponding static and dynamic resistance was found. 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. Conduct the experiment for obtaining the forward bias vi characteristics of the given diode. 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.
To draw the iv characteristic curves of a pn junction diode in forward bias and reverse bias. Such junctions show a pronounced rectifying behavior. Jan 07, 2016 pn junction diode experiment using breadboard and simple components duration. To plot characteristics between reverse saturation current and 10 3t and find out the approximate value of energy band gap in pn junction diode apparatus. To study the characteristics of commonemitter npn or pnp transistor and to find out the values of current and voltage gains.
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. In this type of diode, we dope one side of a semiconductor piece with an acceptor impurity and another side with a donor impurity. If an external potential is applied to the terminals of pn junction, it will alter the potential between the p and nregions. 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 capacitance measurement will be performed on a speci c parameter analyzer. Pdf electrical characterization of a pn junction diode. They provide a lowcost and no frill method for voltage regulation. The pn junction the pn junction is a homojunction between a ptype and an ntype semiconductor.
The pn junction is the fundamental building block of the electronic age. Connect the diode to the pn junction setup as shown in the figure 1. A pnjunction diode is formed when a ptype semiconductor is fused to an ntype semiconductor creating a potential barrier voltage across the diode junction. To study the forward and reverse bias characteristics of diode and zener diode. A pn junction diode allows electric current when it is forward biased and blocks electric current when it is reverse biased. For correct voltage regulation, we need to find out precisely what voltage should be across the zener diode. To find cutin voltage for silicon pn junction diode. Jan, 2015 pn junction diode characteristics lab expriment 1.
Experiment 1 vi characteristics of diode 1 vi characteristics of diode aim. We imagine that one can bring both semiconductor regions together. Definition ptype semiconductor is suitably joined to ntype semiconductor,to conduct surface is called pn junction. A semiconductor diode is prepared by joining p and n sections of a semi conducting. 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. 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. Vi characteristics of pn junction diode in 3biasing modes.
Plot a graph with reverse voltage along x axis and reverse current along y axis. Observation of characteristics of a zener diode debangshu mukherjee bs. The lead connected to the ptype material is called. Due to this characteristic, the diode finds number of applications as given below. Diode allows current to pass in only one direction.
Pn junction diode and characteristics of pn junction diode. The zener breakdown voltage is the minimum reverse biased voltage below which the diode blocks the reverse. Lab 2 pn junction diode characteristic prelab objective. A pn junction diode normally does not conduct when reverse biased. In the positive half cycle, during the time interval 0 to t2, diode d will be forward biased and conduct, i. A pn junction diode is a twoterminal electronics element, which can be classified as either. The critical parameter of this type of diodes is the zener breakdown voltage. Pn junction diode is symbolically represented as shown in picture. A junction diode is formed when a ptype semiconductor is in intimate contact with ntype semiconductor. Objective the objective of this experiment is to measure the iv curve for pn junction diode and to understand the characteristics of pn junction. To study and verify the functionality of a pn junction diode in forward bias b pointcontact diode in reverse bias components equipments required. Jan 29, 2019 pn junction diode is one of the fundamental elements in electronics. Simulator procedure as performed through the online labs select the characteristics of diode from the drop down list.
Measurements of temperature and voltage will be done using a thermocouple and an ad converter respectively. This threshold voltage concept comes from the fact that a diode is just a pn junction. Figure 1 at the junction initially free charge carriers. The direction of arrow is the direction of conventional current flow under forward bias. The forwardbiased voltage of diode is its barrier potential while the reversebiased voltage of diode is infinite over range which shows that the diode is in healthy condition. Pn junction diode is one of the fundamental elements in electronics. Also, it explains the phenomenon of shockleyqueisser limit.
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