The V-I characteristics of a diode can be forward or reverse. Fig.2: V-I Characteristics of pn Junction. 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 region around the p-n junction having no mobile charge carriers is known as depletion region or depletion layer or space charge region. The holes diffuse through the junction from higher concentration region (p-region) to lower concert region (n-region). 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. Conclusions: (a) V-I graph for diode is not a straight line passing through the origin. The movement of holes and electrons constitute diffusion hole current (Ih) and diffusion electron current(Ie) respectively. We know a diode has a depletion region with a fixed barrier potential. Characteristics of a p-n junction diode It generally shows the relation between bias voltage and current of a diode. The potential barrier of height Vb of unbiased p-n junction is also shown in the figure. admin 09/01/2021 10 0. 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. Depletion region created across the pn junction by the initial movement of majority carrier across the junction. In a P-N junction Diode, we will consider the p-n junction with a forward-bias voltage employed. When a diode is reverse biased a leakage current flows through the device. A PN Junction Diode is a two-terminal semiconductor device. a forward potential difference of V volt is applied across the diode. PN Junction Diode VI Characteristics in Reverse Bias Therefore, this is all about PN junction diode in zero bias, forward bias and reverse bias conditions and VI characteristics of PN junction diode. (1), it is a two-terminal device where the terminal A stands for … P-N junction diode in the reverse-biased configuration is sensitive to light from a range between 400nm to 1000nm, which includes VISIBLE light . Indicate the differences between the characteristics of silicon and germanium diodes and state approximately their cut-in voltages. The circuit connection for determining the V-I characteristics of a pn junction is shown in the figure below. 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 resistance of a diode is the function of the operating current. PN Junction Diode VI Characteristics. A diode is a two-terminal unidirectional power electronics device. If the reverse bias in increased to a high value, the covalent bonds near the junction break down and a large number of electron-hole pairs are liberated. 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. Characteristics of a p-n junction diode It generally shows the relation between bias voltage and current of a diode. We hope that you have got a As we already know, there are few free electrons in p-type material and few holes in n-type material. The holes (majority carriers) in p-region and electrons(majority carriers) in n-region acquire sufficient energy to overcome the potential barrier across the junction. Hi! Characteristics of a p-n junction diode It generally shows the relation between bias voltage and current of a diode. 2 PN Junction Diode 3 Power Diode Characteristics The circuit symbol can be seen in Figure. P-N Junction Diode: A P-N Junction Diode is one of the simplest semiconductor devices around, and which has the characteristic of passing current in only one direction only. Normally the voltage is taken along the x-axis and current along y-axis. It is a special type of diode which operates in the breakdown region. The variation of current with the applied voltage across the junction diode gives the characteristics of p-n junction diode. The V-I characteristics or voltage-current characteristics of the p-n junction diode is shown in the below figure. In the Forward Bias, the … For germanium diode, the knee voltage is about 0.2 V, whereas for silicon diode it is about 07 V. When forward voltage is above the knee voltage, the junction diode behaves almost like a conductor. Enable registration in settings - general, P-N Junction Diode Formation ,Work & Its Characteristics| Electronics Tutorial |, Semiconductor diode or p-n junction diode, Working of p-n junction diode under forward bias, Working Of p-n junction diode under Reverse bias, Static and Dynamic resistances of a Junction Diode, Explain reverse biasing in a p-n junction diode, Explain forward biasing in a p-n junction diode, explain the V-I characteristics of a p-n junction diode in forward biasing and in reverse biasing, What is junction barrier or potential barrier, What is a Photodiode, LEDs, Solar Cells & Opto Electronic Devices | Electronics Tutorial |. PN Junction diode If one side of a single crystal of pure semiconductor (Ge or Si) is doped with acceptor impurity atoms and the other side is doped with donor impurity atoms, a PN junction is formed as shown in Fig. PN junction diode shows zero resistance in the forward direction and infinite resistance in the reverse direction. The PN-junction diode is connected in forward biased by keeping the key K close and keeping the double throw switch in position one. This type of information may be obtained by a curve known as Volt-Ampere (V-I) characteristics of a practical diode. I am Sasmita . In reverse bias condition , the p-type of the pn junction is connected to the negative terminal and n-type is connected to the positive terminal of the external voltage. The V-I characteristics of a diode can be forward or reverse. The Zener diode is made up of silicon material. The circuit diagrams to study forward bias characteristic of p-n junction diode is shown in figure 10. A PN junction diode in forward bias mode, the depletion width decreases. The most basic device is diode. When this PN junction diode is now connected to an external voltage, this can effectively increase or decrease the built in potential gap. The junction of N and P semiconductors is free of charge carriers; hence the region is called as depletion region. From the forward characteristics, it can be noted that at first i.e. Explain forward biasing in a p-n junction diode with the help of diagrams. Semiconductor diode consists of a p-n junction having metallic contacts at both the ends as shown in figure 7(A). The V-I characteristics of a diode can be forward or reverse. Explain V–I characteristics of a PN junction diode. The potential barrier, of p-n junction is represented by figure 6. This depletion region has a predefined width, say W. This width will vary for a Silicon diode and a Germanium diode. It is used in the construction of transistors, FET, Gates and many other types of integrated circuits. 5.5. Here, the characteristics is the graph where the voltage is plotted on the X-Axis and the Current on the Y-Axis. We have also learned about diffusion current Electronics and Communication Engineering Questions and Answers. i.e., it is not a perfect diode. 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). There is small current due te the minority carriers. (b) The resistance across the junction of a diode in large below the knee voltage . The basic device formed from this p-n junction is of two terminals. At some forward voltage i.e 0.7 V for Si and 0.3 V for Ge, the potential barrier is almost eliminated and the current starts flowing in the circuit. 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. 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. (c)The resistence across the junction of a diode decreases above the knee voltage. Useful mathematical relations are How is this layer or region formed ? A p-n junction diode when not connected to a cell or battery is shown in figure 8(A). Hence. When the battery voltage is zero (1.e. The PN junction region of a Junction Diode has the following important characteristics: Semiconductors contain two types of mobile charge carriers, “Holes” and “Electrons”. The two important processes called diffusion and drift occur during the formation of p-n junction. 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. region OA , the current increases very slowly and the curve is non-linear. A zener diode when reverse biased can either undergo avalanche break down or zener break down. Fig.1: Circuit Connection for V-I characteristics of a pn junction. As a result of this, large electron-hole pairs are produced which diffuse through the junction and hence there is a sudden rise in the reverse current (figure 13). After that many types of diodes are invented. Non Ideal PN Junction  Real diode characteristics V A high level injection recombination at depletion ideal resistive log(I) •At low current, the measured current is larger than the ideal current •When the bias voltage increase to close to V Bi, the diode current, the current increase is slowed down Mansunansun The forward characteristic of a PN junction diode is non linear, i.e., not a straight line. V-I characteristics of p-n junction diode. 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