Imagine a pn junction with metallic contacts at both the ends for application of external voltage. Zener diode experiment viva questions with answers characteristics mcqs interview questions. Zener diode applications chapter 3 overview zener diodes zener characteristics zener diodes diode types rectifier zener lower vz due to more heavily. Semiconductor diode questions and answers pdf free download mcqs interview objective type questions for eee ece electronics students semiconductor diode. V t1 where i do is reverse saturation current and will be very high in tunnel diode compared to pn junction diode due to high doping concentrations. It is the most essential and the basic building block of the electronic device. The result is that some of the free electrons from the donor impurity atoms begin to.
Semiconductors and diodessemiconductors and diodes. The diode current in a tunnel diode is same as that for normal pn junction diode which is given as i diode i do exp v. Experimental methods py2108 2 1 learning objectives the objectives of this practical section are to 1. To study the characteristics of commonemitter npn or pnp transistor and to find out the values of current and voltage gains. 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. By applying an external voltage v we can vary the potential barrier. 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 is a twoterminal device which conducts current only in one direction. Electrical and telecommunications engineering technology department. Figure 1 at the junction initially free charge carriers. It generally shows the relation between bias voltage and current of a diode. Conduct the experiment for obtaining the forward bias vi characteristics of the given diode. Effects of the energygap shrinkage, the highlow junction builtin voltage, the highlevel injection, and the minoritycarrier life time on the forwardbiased currentvoltage characteristics are.
Iv characteristics pn junction iv characteristics electron drift flow electron diffusion flow electron diffusion flow electron drift. The forwardbias and the reversebias properties of the pn junction imply. Obtain the traces for the diode voltage and current and store them in the data files using the scope remote control interface. Zener diode lab viva questions and answers pdf free download. Experiment 1 vi characteristics of diode 1 vi characteristics of diode aim. If a suitable positive voltage forward bias is applied between the two ends of the pn junction, it can supply free electrons and holes with the extra energy they. The boltzmann approximation is to say that the resulting current being small compared with the components of. Observation of characteristics of a zener diode debangshu mukherjee bs. 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 property of diode makes it an essential component of. A pn junction is a boundary or interface between two types of semiconductor materials, ptype. The junction is said to be reverse biased when the psection of the diode is connected to the negative terminal of the battery and the psection of the diode is connected to the positive terminal of the battery. Diode allows current to pass in only one direction. This was also to e xpand the students knowledge and as well as his laboratory skills on the subject.
Full practical pn junction diode with readings, download pdf. Semiconductor diode forward bias and reverse bias byjus. Diode pn junction when p and n type silicon are brought together during manufacture, a junction is created where the p type and n type materials meet, and holes close to the junction in the p type silicon are attracted into negatively charged n type material at the other side of the junction. To draw the iv characteristic curves of a pn junction diode in forward bias and reverse bias.
Pn junction properties calculator pn junction lab free to use on. This causes electrons from nregion to get attracted to positive terminal of the battery and holes by the negative terminal. Ppt pn junction diode powerpoint presentation free to. Smith department of eecs university of california, berkeley eecs 105 spring 2004, lecture 19 prof. Pn junction diode and characteristics of 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. Working of pn junction diode with biasing, characteristics. Pn junction diode baising and its vi characteristics. A pn junction diode will let current go in only one direction forward bias. Junction diodes questions and answers electronics post.
The figure above represents the symbol for pn junction diode, which symbolizes the direction of the current. A pn junction diode is formed by joining together ntype and ptype silicon. Conclusion this experiment focuses on the investigation of the basic characteristics of a diode. Here, majority carriers from both sides move away from the junction and thus no current flows through the junction. 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. To study and verify the functionality of a pn junction diode in forward bias b pointcontact diode in reverse. Ppt zener diode applications powerpoint presentation. To find the static and dynamic resistances in both forward and reverse biased conditions for pn junction diode. A pn junction diode is a twoterminal electronics element, which can be classified as either step graded or linear graded. Such junctions show a pronounced rectifying behavior.
This was conducted as an introductory to electronics laboratory and in line with some topics in lecture classes. To draw the characteristic curve of a zener diode and to determine its reverse break down voltage. We have seen that the diode can conduct only when it is forward biased and blocks when it is reversed biased. The junction of n and p semiconductors is free of charge carriers. We have also learned about diffusion current, depletion region. Outline semiconductor physics the pn junction biasing the pn junction the diode. The adobe flash plugin is needed to view this content. A free powerpoint ppt presentation displayed as a flash slide show on id. Semiconductor diode questions and answers pdf free download posted on august 19, 2018 march 20. Prepared by textbook based on electronics devices by floyd, prentice hall, 7. A pn junction is the metallurgical boundary between the n and pregions of a semiconductor crystal. 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. To find the cutinvoltage for silicon pn junction diode.
The pn junction is a versatile element, which can be used as a. Pn junction diode is a two terminal device, the characteristics of diode depends on the polarity of the external potential applied to the pn junction diode. Pn junction diode is one of the fundamental elements in electronics. Pn junction diode vi characteristics using multisim youtube. Iv characteristics of forward and reverse biased pn junction diode. The basic bipolar transistor or bjt is two diodes constructed back to back on a piece of silicon. Tunnel diode working principle and characteristics ece. Effects of the energygap shrinkage, the highlow junction builtin voltage, the highlevel injection, and the minoritycarrier life time on the forwardbiased currentvoltage characteristics are included.
Pn junction underbiasing 14 boltzmanns approximation. It is also important to note here that the equilibrium barrier potential can be altered. If current is applied in the opposite direction reverse bias then we would not have current on the other end unless the voltage that you apply to it surpasses its. Understand the behaviour of a diode under forward and reverse bias and be able to plot the iv characteristic of an ideal diode 3. Understand the physics of a pnjunction and how a junction diode is created 2. A pn junction diode allows electric charges to flow in one direction, but not in. Zener diode is a pn junction diode specially designed for operation in the breakdown region in. 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 very small current will made at the junction due to the movement of minority charge carriers across the junction. Basic electronics nyu tandon school of engineering. Rectifier circuits introduction we have studied the operation and iv characteristics of a pn junction diode in the previous experiment. The result of this process is that the pn junction has rectifying currentvoltage iv or iv characteristics. This is the basic construction of the pn junction diode. Movement of electrons and holes when forming the junction circles are charges free to move electrons and holes squares are charges not free to. To study and verify the functionality of a pn junction diode in forward bias b pointcontact diode in reverse bias components equipments required. Diodes and diode circuits tlt8016 basic analog circuits. 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. Pn junctions consist of two semiconductor regions of opposite type.
Download file pdf b sc practical physics cl arora class 12,physics expt. Simulation using multisim of pn junction diode characteristics. Vi characteristics of pn junction diode in 3biasing modes. Diode a diode is a 2 lead semiconductor that acts as a one way gate to electron flow. Electrical characterization of a pn junction diode using keithley 2400 source measure unit. Pdf electrical characterization of a pn junction diode. Electronics tutorial describing the semiconductor pn junction and pn junction theory of. Review, pn junctions, fermi levels, forward bias prof j.
Conclusion this experiment focuses on the investigation of. 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. They are also called pn diodes in analogy with vacuum diodes. Objective the objective of this experiment is to measure the iv curve for pn junction diode and to understand the characteristics of pn junction. From the experiment, the following conclusions were drawn. Pn junction diode characteristics experiment edunovus online smart practicals duration. The undesirable free electrons in ptype and holes in n type are called minority carriers. In this type of diode, we dope one side of a semiconductor piece with an acceptor impurity and another side with a donor impurity. Pn junction iv characteristics electron diffusion current negligible due to large energy barrier electron drift.
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