EST 130 BASICS OF ELECTRONICS ENGINEERING || PN JUNCTION DIODES || KTU

Hi all. Welcome to the 7th lecture of Basic Electronics. Today we are going to discuss about PN Junction Diodes. You must have heard about Diodes. What is PN Junction? A PN Junction is called as a PN Junction Diode or a Semiconductor Diode. This PN Junction Diode is called as a Semiconductor Diode. PN Junction Diode is a Unidirectional Two Terminal Semiconductor Device. What is a Unidirectional? The current conduction is only in one direction. That is called as a Unidirectional. PN Junction Diode is a Two Terminal Semiconductor Device. It has two terminals. This is the terminal. Anode and Cathode. PN Junction Diode is a Semiconductor Device with two terminals. This is a Unidirectional. The current conduction is only in one direction. This is the Anode and Cathode. The current conduction is only in one direction. In practice, a PN Junction is formed by simply joining or fusing together two separate pieces of P and N Type Semiconductors. Electrical Conducts are used for the terminals. Electrical Conducts are fused in the two sides of the crystal. It is a two terminal device. It has two terminal. Anode and Cathode. The P-type region is called anode and the N-type region is called cathode. This is the symbol of a diode. This triangle region is called anode. This line is called cathode. This is how a PN junction diode is available in the market. This is the diagram of a PN junction diode. The next two terms are the depletion region formation and the barrier potential. This is how a PN junction diode forms a P-type semiconductor. The majority carriers of the P-type region are holes. This is the P-type region. These holes are the majority carriers of the P-type region. The minority carriers of the P-type region are electrons. The majority carriers of the P-type region are holes. The minority carriers of the P-type region are electrons. The majority carriers of the P-type region are electrons. The majority carriers of the P-type region are immobile ions. The majority carriers of the N-type region are electrons. The majority carriers of the P-type region are electrons. The minority carriers of the N-type region are holes. The majority carriers of the P-type region are positive charged immobile ions. This is how a p-type semiconductor and a n-type semiconductor looks like. Now we have fused both of them together to form a p-n junction. Now let's see the process that goes on inside this. Once the p-n junction is formed, the process shown below will take place inside this. What happens is, the holes inside this, the holes in this p-region, the holes in this p-region are these small circles. These holes will go to the n-region. The electrons here will go to the n-region. Similarly, the electrons seen in the n-region will move towards the p-region. The electrons seen here will move towards p-region. Similarly, the holes in the p-region can be attracted to the electrons in the n-region. Later on, the electrons in the n-region can be recombined with the holes in the p-region. A recombination will take place. If we recombine these ions, we can create an electron hole pair. We can create an immobile charged ion. This is called an electron hole pair. We can create an immobile charged ion. These ions will be at the boundary of the charge. These ions will be at the junction. These ions will accumulate at this junction. This region is called the depletion region. These ions are in the depletion region. These ions are electrically charged. This is called the space charge region. These are the immobile ions. These are the electrically charged ions. This is called the space charge region. I will show you the basic workings of this. You will understand if you look at this. These are the things I mentioned earlier. The electrons in the P and N regions move to the P region. Similarly, the holes in the P region move to the N region. An electron hole pair will be created there. An electron hole pair will be created at the boundary of the junction. The electron hole pair will be at the junction. The depletion region is at the junction. The immobile ions will be at the depletion region. This is the basic workings of this. The space charge region is created by the immobile ions. The electric field stops the diffusion process of the immobile ions. This electric field creates a potential difference at the junction. This potential difference is called barrier protection. Barrier is a barrier. The electrons in the P region move to the N region. The holes in the P region move to the N region. The electrons in the N region move to the P region. This is called diffusion. The diffusion process stops. A barrier is created at the junction. This barrier creates a potential difference at the junction. This potential difference is called barrier protection. This potential difference is created at the junction. This is called junction protection. This potential difference is called space charge protection. The barrier potential is measured in volts. In silicon, the barrier potential is 0.7 V. In germanium, the barrier potential is 0.3 V. E0 is equal to VT ln NdNa divided by Ni2. E0 is the barrier potential. VT is the thermal voltage. The value of the thermal voltage is 26 mV. It is a constant value at room temperature. Nd and Na are donor impurity concentration, donor ion concentration and acceptor ion concentration. Nd and Na are impurity concentrations. Ni is intrinsic concentration. The holes in the P region move to the N region. The electrons in the N region move to the P region. An electron hole pair is created. Immobile ions are created. These ions move to the P region. Immobile ions create a region. This region is called the depletion region. The depletion region is related to doping. If the doping level is high, the width of the depletion region will be narrow. If the doping level is low, the width of the depletion region will be high. If the doping level is high, the width of the depletion region will be low. The width of the depletion region is related to the barrier potential. If the width of the depletion region is high, the doping level is low. The barrier potential will be high. The width of the depletion region depends upon the doping level of impurity in the N-type and P-type semiconductor. These are the basics of the diode. In the next lecture, we will discuss the biasing of the diode. I hope everyone understood this class. See you in the next lecture.