The flow of drift current is opposite to the flow of diffusion current set up due to the diffusion of electrons and holes through the junction (Figure 5). On the other hand, when electrons diffuse through the junction, the n-region near the junction is left with positive ions (or donor or) fixed in their positions in the crystal lattice. The electrons and holes travel in opposite directions, but they also have opposite charges, so the overall current is in the same direction on both sides of the diode, as required. As we already know, there are few free electrons in p-type material and few holes in n-type material. Physics practical to study about PN junction diode and obtain its V-I (voltage, current) characteristics until breakdown voltage and plot graph with diagram. 2. If the diode is used as a circuit element in an electrical circuit, there may be a requirement to know how it responds or behaves in an electric circuit. When this PN junction diode is now connected to an external voltage, this can effectively increase or decrease the built in potential gap. Volt-ampere (V-I) characteristics of a pn junction or semiconductor diode is the curve between voltage across the junction and the current through the circuit. Form this instant, the current increases with the increase in forward voltage. This is characterized by a sudden increase of reverse current and a sudden fall of the resistance of barrier region. P-N junction diode in the reverse-biased configuration is sensitive to light from a range between 400nm to 1000nm, which includes VISIBLE light . A PN junction diode is a two-terminal electronic component that allows the flow of electric current only in one direction. As a result of this, holes in the p-region and electrons in the region cannot cross through the junction. D.C. or Static resistance of the diode is defined as the ratio of the d.c. voltage across the diode to the direct current flowing through it. The majorly used diodes … A zener diode when reverse biased can either undergo avalanche break down or zener break down. 2 PN Junction Diode 3 Power Diode Characteristics The circuit symbol can be seen in Figure. A p-n junction is said to be forward biased when the positive terminal of a cell or a battery is connected to p-side and the negative terminal of the cell or the battery is connected to the n-side of the junction diode. The basic device formed from this p-n junction is of two terminals. When a cell or a battery is connected across the p-n junction diode such that positive terminal is connected to p-region and negative terminal is connected to n-region (figure 8(b)]. The circuit diagrams to study forward bias characteristic of p-n junction diode is shown in figure 10. Useful mathematical relations are The 'P' side of a pn junction diode is always positive terminal and is called as anode. When holes diffuse through the junction, the p-region near the junction is left with negative ions (or acceptor ions) which remain fixed in their positions in the crystal lattice. i.e., it is not a perfect diode. To plot Volt-Ampere Characteristics of Silicon P-N Junction Diode. This potential difference reduces the potential barrier (Vb). The difference in concentration with distance (i.e. However, unlike a resistor, a diode does not behave linearly with respect to the applied voltage as the diode has an exponential current-voltage (I-V) relationship. I am Sasmita . ... P-N Junction Diode Formation ,Work & Its Characteristics. The V-I characteristics or voltage-current characteristics of the p-n junction diode is shown in the below figure. Usually voltage is taken across x-axis and current along y-axis. PN junction diode shows zero resistance in the forward direction and infinite resistance in the reverse direction. concentration gradient) makes the injected holes and electrons diffuse to the ends of n-side and p side respectively. The holes diffuse through the junction from higher concentration region (p-region) to lower concert region (n-region). The most basic device is diode.Diode is a two terminal PN junction device. What is a rectifier ? (1), it is a two-terminal device where the terminal A stands for … (c)The resistence across the junction of a diode decreases above the knee voltage. In forward biased condition , p-type of the pn junction is connected to the positive terminal and n-type is connected to the negative terminal of the external voltage. Here, the characteristics is the graph where the voltage is plotted on the X-Axis and the Current on the Y-Axis. This current attains its maximum or saturation value immediately and is independent of the applied reverse voltage, It depends on the temperature of the junction diode. Voltage-Current Characteristics of a PN Junction Diode To draw the voltage-current (V- I) characteristics of the PN junction diode and to determine its knee voltage and forward resistance. Semiconductor PN Junction Diode is the simplest semiconductor 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. A p-n junction formed by the doping f p-type and n-type material on a single crystal. The V-I characteristics of a diode can be forward or reverse. Construction and Working of PN Junction Diode. In a junction diode, current does not linearly follow applied voltage, so it does not strictly obey Ohm’s law. The crossed over electrons in p region and holes in n region are in fact minority carriers so this process of cross over is called minority carrier injection. A p-n junction diode when not connected to a cell or battery is shown in figure 8(A). PN junction is formed by bringing a P type material in contact with N type material. When P and N semiconductors are joined to make the PN junction semiconductor diode, the electrons near the PN junction jump from N to P and holes near the junction jump from P to N. A p-n junction when not connected to a cell or battery is shown in figure 9(A). V-I Characteristics stands for voltage and current. However, once the external voltage exceeds the potential barrier voltage, the potential barrier is eliminated and the pn junction behaves as an ordinary conductor. A P-N Junction Diode is formed by doping one side of a piece of silicon with a P-type dopant (Boran) and the other side with a N-type dopant (phosphorus).Ge can be used instead of Silicon. A cell or a battery can be connected across the metallic contacts of the p-n junction diode. Using circuit diagram and graphs, explain the V-I characteristics of a p-n junction diode in forward biasing and in reverse biasing. Symbolic representation of a p-n junction diode is given in figure 7(B): The arrowhead represents p -type semiconductor and the vertical bar represents n-type semiconductor. What is a p-n junction diode? V-I Characteristics of PN Junction Diode. Avalanche break down:-If both p-side and n-side of the diode are lightly doped, depletion region at the junction widens. The semiconductor diode is the first invention in a family of semiconductor electronics devices. When a cell is connected in reverse mode to the p-n junction diode as shown in figure 9(B), a potential difference of V volt is applied across the diode. Characteristics of a p-n junction diode It generally shows the relation between bias voltage and current of a diode. The following are the vital characteristics of a PN junction region (junction diode): A semiconductor consists of two types of mobile charge carriers: electrons, and holes. Similarly, electrons diffuse through the junction from n-region to p-region and combine with holes in p-region and hence get neutralized. A PN-junction is said to be condition when an N-type material is combined together with a P-type material creating a semiconductor diode. At this stage breakdown of the junction may occur. Volt-ampere characteristics of diode in forward bias condition.2. The thickness of depletion layer is about (0-5 um.). Once break down voltage is reached any increase in the applied voltage leads to the high reverse current which may damage a simple junction diode. A diode is a two-terminal unidirectional power electronics device. Forward V-I characteristics of p-n junction diode If the positive terminal of the battery is connected to the p-type semiconductor and the negative terminal of the battery is connected to the n-type semiconductor, the diode is said to be in forward bias. The potential barrier, of p-n junction is represented by figure 6. A small quantity of trivalent impurity say indium is fused to a thin wafer (i.e., very thin slice) of n-type germanium or silicon semiconductor. PN Junction Diode Characteristics The following are the vital characteristics of a PN junction region (junction diode): A semiconductor consists of two types of mobile charge carriers: electrons, and holes. PN Junction Diode VI Characteristics. A zener diode when forward biased behaves like an ordinary P-N junction diode. When a diode is reverse biased a leakage current flows through the device. The potential barrier of this p-n junction is reduced when a forward-bias voltage is applied to it. 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