One terminal of p-n junction diode is Anode and other is cathode. Static resistance of a diode is defined as the ratio of the DC voltage applied across the diode to the DC current flowing through the diode. This state is reached after 5 microseconds. The first thing that we shall be interested in is about “barrier potential”. When the p-n junction is forward biased, the built-in electric field at the p-n junction and the applied electric field are in opposite directions. thanx ! PN Junction diode is a device made of two semiconductor material joined together with the required amount of impurity. Story behind Invention & Discovery of PN Junction, Magneto Resistor – Symbol, Working, Types & Characteristics, Carbon Film Resistor – Working, Construction & Applications, Photoresistor – Symbol, Working, Types & Applications, https://www.circuitstoday.com/full-wave-bridge-rectifier. Here the interesting thing to note is that, diode does not conduct with change in applied voltage. We know a diode has a depletion region with a fixed barrier potential. will you please show the one connected image source circuit of both forward and reverse biased a pn-junction, wow it is very much helpful to me. History of Diode: In the year 1940 at Bell Labs, Russell Ohl was working with a silicon crystal to find out its properties. VI Characteristic of PN Junction Diode. Now this is what we call “characteristics of a pn junction diode” or the “behavior of diode under forward bias”. If we add a small amount of pentavalent impurity to this, a part of the p-type Si will get converted to n-type silicon. As the applied voltage increases from 0 volts to 0.7 volts, the depletion region width reduces from ‘W’ to zero. 9. From this data what you can infer ? It is used to convert AC to DC. The diffusion current; The drift current; The displacement current; None of these; Answer – (2) 10. Understanding about the P-N Junction Diode Theory and Working. Very helpful article. The diode operates in the transmission mode and the output voltage equal to the input voltage. 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. MCQs on PN junction diode for NEET 2021 The interface or the boundary between the p-type and n-type semiconductor is called PN junction. To apply an external voltage, we usually connect 2 metallic contacts at the two ends of the pn junction (known as terminals); one on the p-side and other on the n-side. During reverse bias, the diode does not conduct with increase in voltage (break down usually results in damage of diode). oh thank u..i am very confused to read my text book but now every thing is clear….thank you very much And in reverse bias condition the depletion region increases instead of decreasing. Required fields are marked * Comment. Its in conversion of alternating current to direct current (AC to DC). Dynamic resistance of a diode is defined as the ratio of change in voltage to the change in current. Leave a Reply Cancel reply. PN junction diode is symbolically represented as shown in picture. Utmost/extremly thanks ….. Similarly, when a hole goes from the p-side to the n-side, and ionized acceptor is left behind in the p-side, resulting in the formation of a layer of negative charges in the p-side of the junction. hoping that 2 give more information about electronics. We have learned that if we apply an external voltage higher than the barrier potential of pn junction diode, it will start conducting, which means it will start passing current through it. Let us consider a thin p-type silicon semiconductor sheet. it is so helpful and it clears all the confusion…….plz answer meone question thatis why in CB mode the emitter current increases with increase of V(CB), this is a exellent article……….sir plz letme know about base width modulation, It is very short notes As I see it, we just consider 0.7V as a practival value for a conducting diode, where any variation of the current will cause a small variation on Vd, keeping it around the same 0.7V. This completes the reverse bias circuit for pn junction diode. So “barrier potential” of a Silicon diode is higher than Germanium diode. The two breakdown mechanisms are Zener breakdown and Avalanche breakdown. The width highly depends on the type of semiconductor used to make pn junction, the level of doping etc. eval(ez_write_tag([[468,60],'circuitstoday_com-medrectangle-3','ezslot_2',124,'0','0']));Note:- I have written an interesting article which tells the story behind invention & discovery of PN Junction diode. in forward biasis -VE terminal of battery is connected to pentavelent group N and +ve is connected to trivalent group P but in reverse biasis the connection is opposite …, very clear presantation if you were around i would offer you a cup of tea or coffee good work. admin 09/01/2021 10 0. This means that greater the intensity of light on the PN junction of a Photo-diode, the greater will be the reverse current in the Photodiode. That was a comprehensive expose. We can determine the current-voltage characteristics. This sheet will now contain both p-type region and n-type region and a junction between these two regions. The potential barrier of this p-n junction is reduced when a forward-bias voltage is applied to it. A P-N junction diode is a combination of two semiconductor materials, one is P-type semiconductor and another is N-type semiconductor. For this crystal clear explanation….. When the voltage is raised above a particular point, say 80 volts, the current suddenly shoots (increases suddenly). In any PN junction diode, the P region contains holes as it has been doped to make sure that it has a majority of holes. This depletion region has a predefined width, say W. This width will vary for a Silicon diode and a Germanium diode. What really happens inside the diode during the forward bias ? The movement of charge carriers inside the pn junction is the reason behind the current flow in the circuit. 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