1. In the reverse biased mode zener diode has large breakdown voltage and though the current increases the voltage remains constant. First, we will look at the general laboratory experiment and it’s format. The Zener conducts the least current when the load current is the highest and it conducts the most current when the load current is the lowest. Zener diode has the property of behaving like a dc battery in ‘on’ state (i.e. Plot the reverse characteristic curve by taking reverse voltage along –ve X-axis and reverse current along –ve Y-axis. b. ZENER DIODE CHARACTERISTICS EXPERIMENT 2018 - Duration: 6:58. If we operate an ordinary diode in reverse biased, it conducts insignificant current until the voltage applied across them exceeds the … To calculate static and dynamic resistances of the Zener diode in both forward and reverse biased conditions (before, after break down voltages). The I-V Characteristics Curve of a zener diode, shown below, is the curve which shows the current-voltage relationship of a zener diode. Characteristics of Zener Diode. In the reverse bias condition the Zener diode is an open circuit and only a small leakage current is flowing as shown on the exaggerated plot. The zener diode characteristics have been studied. Varying amount of reverse current can pass through the diode without damaging it. Shunt regulators have an inherent current limiting advantage under load fault conditions because the series resistor limits excess current. From the plot at which point of voltage the spike in current is noticed that voltage value is referred to as Zener … 9. What are the different types of breakdowns in semiconductor junctions? What will happen if P-N regions are heavily doped in Zener diode? This is an individual effort but members of a team can and should share insight, confirm results, and help problem solve. Zener doide is a special diode with increased amounts of doping. Ans: A zener is designed to operate stably in reverse breakdown, which is designed to be at a low voltage, between 3 volts and 200 volts. However, when reverse biased voltage is applied to the zener diode, it works in different manner. You can use the embedded worksheet to enter the values. We use Zener diodes for voltage regulation and voltage stabilisation. Zener Diode Characteristics. The I-V Characteristics Curve of a zener diode, shown below, is the curve which shows the current-voltage relationship of a zener diode. In a standard diode, the Zener voltage is high, and the diode is permanently damaged if a reverse current above that value is allowed to pass through it. (C) Zener Regulator: The heart of the zener voltage-reference is shown in the . 21. 6. Connect the CRO CH1 across the input and CH2 across resistor. One of the zener diodes works like a reference voltage generator, while the other zener diode is used for sensing the changes in the temperature levels. 4-6 3. 2. Ans:Zener diode is a heavily doped P-N junction diode, which conducts in reverse bias. This may lead to damaging of the diode. Theory: A Zener Diode is constructed for operation in the reverse breakdown re-gion.The relation between I-V is almost linear in this case Vz =Vz0+Iz Rz, where Rz is the dynamic resistance of the zener … APPARATUS:- PROCEDURE: FORWARD BIAS CHARACTERISTICS 1. The most common values for nominal working voltage are 5.1 V, 5.6 V, 6.2 V, 12 V and 15 V. We also carry Zener diodes with nominal working voltage up to 1 kV. ... Take the readings until a Diode Current of 30mA. To redo the experiment, click on the ‘Reset’ button. Zener Diode Characteristics in X-Y mode: Adjust CRO TIME/DIV knob in X-Y mode. h) Bias Current (I2) Stability Noise 9 _:5% . If both p-side and n-side of the diode are lightly doped, depletion region at the junction widens. 7-9 4. Connect the CRO CH1 across the input and CH2 across resistor. The readings of voltage and current are tabulated. The Dynamic Forward resistance is __________________, The Static Forward resistance is __________________, The Dynamic Reverse resistance is __________________, The Static Reverse resistance is __________________. As the applied reverse voltage increases the minority carriers acquire sufficient energy to collide with the carriers in the covalent bonds inside the depletion region. When forward biased voltage is applied to the zener diode, it works like a normal diode. Forward characteristics are similar to both, although the zener's forward characteristics is usually not specified, as the zener will never be used in that region. Ans: Zener diodes are widely used as voltage references and as shunt regulators to regulate the voltage across small circuits. Ordinary diodes are forward biased and work in the forward direction. Result: The characteristics and Voltage Regulation of Zener diode are studied. EXPERIMENT REQUIREMENT Components and Equipments a. Zener Diode (1N753) b. UNI-T Digital Multi-meter (UT 55) C. Variable Resistor (1 KO) d. GW Instek Oscilloscope (GOS-630FC) e. Resistor(33012,470N, 4.7K2, 47K22) f. K & H MFG. # Characteristics of a Zener Diode The above diagram shows the V-I characteristics of the Zener diode behavior. Connect the Circuit as per the Circuit Diagram on the bread board. In ‘on’ state , the voltage across zener diode remains constant until the voltage across it deops less than VZ . 2. Procedure: Forward Bias Characteristics: 1. Here the Zener diode acts like an ordinary diode. Theory Zener Diode. Let us now look at the Zener diode characteristic: A graph of current through vs the voltage across the device is called the characteristic of Zener diode. So exceeding the reverse voltage may result in the device being damaged. The typical forward voltage at room temperature with a current of around 1 mA is around 0.6 volts. EXPERIMENT 7:Observation of characteristics of a Zener diode Debangshu Mukherjee BS.c Physics,1st Year Chennai Mathematical Institute 7.11.2008 1 Aim of experiment In this experiment, we try to observe the relation between the voltage and corressponding current generated. Rectifiers (without and with c-filter) Part A: Half-wave Rectifier Part B: Full-wave Rectifier 4. It should be replaced. Zener diodes are also known as a) Voltage regulators b) Forward bias diode c) Breakdown diode d) None of the mentioned. A standard 10 V Zener may have a temperature coefficient of +0.07%/ °C which may correspond to 7 mV/ °C variation in temperature. Open Diode. At the end of the experiment, the student will be able to ... Zener Characteristics; Select the diode; Set the rheostat R h =1 Ω; By adjusting the rheostat, voltmeter reading is increased from 0 and in each time note the corresponding reading in milliammeter. The Zener diode specially made to have a reverse voltage breakdown at a specific voltage. Ans: The forward voltage at which the current through the junction starts increasing rapidly, is called the knee voltage or cut-in voltage. APPARATUS:- PROCEDURE: FORWARD BIAS CHARACTERISTICS 1. Such sudden increase in the number of charge carriers due to rupture of covalent bonds under the influence of strong electric field is termed as Zener breakdown. To draw the characteristic curve of a zener diode and to determine its reverse break down voltage. In the forward biased mode the zener diode operates as a p-n diode. Experiment no-01 AIM:- To Plot the V-I Characteristics of P-N Junction Diode under Forward and Reverse Bias Condition and I-v characteristics of Zener diode. When the diode is connected in forward bias diode acts as a normal diode. The purpose of a voltage regulator is to maintain a constant voltage across a load regardless of variations in the applied input voltage and variations in the load current. While doing the experiment do not exceed the ratings of the diode. Ohms (!'fax. ) Do not switch ON the power supply unless you have checked the circuit connections as per the circuit diagram. The orientation is very important. The reverse leakage current has been exaggerated to make it show on the graph. Sl No Name of Experiment Page No 1. Theory. A Zener diode is a diode which allows current to flow in the forward direction in the same manner as an ideal diode, but will also permit it to flow in the reverse direction when the voltage is above a certain value known as the breakdown voltage Ans: Reverse breakdown due to avalanche mechanism or Zener effect.In reverse bias a rapid change in the current at break down voltage. As the reverse bias is increased, the Electric field becomes strong enough to rupture covalent bonds and generate large number of charge carriers. A conventional solid-state diode allows significant current if it is reverse-biased above its reverse breakdown voltage. Ans:Peak Inverse Voltage(PIV) of Zener diode is the peak voltage across the diode in reverse direction in reverse bias,it is equal to the break down voltage of zener diode. What are the applications of Zener diode? Objectives: To study the characteristics of Zener diode. Switch on the Regulated Power Supply and slowly increase the source voltage. If the diode reads a much higher voltage, of or near the voltage of the supply voltage feeding it, it is open and, thus, defective. A Zener Diode is a special kind of diode which permits current to flow in the forward direction as normal, but will also allow it to flow in the reverse direction when the voltage is above the breakdown voltage or ‘zener’ voltage.u000b Zener diodes are designed so that their breakdown voltage is much lower - for example just 2.4 Volts. The critical parameter of this type of diodes is the Zener breakdown voltage. The circuit for studying the forward bias characteristics of a Zener diode is as shown in the figure1. Select the diode; Set the rheostat R h =1 Ω; By adjusting the rheostat, voltmeter reading is increased from 0 and in each time note the corresponding reading in milliammeter. But for simplicity, both types are called Zener Diodes. This is a simple test we can do to check whether it is good, open, or shorted. 7.5 . The diagram shows a bridge network built using a pair of resistors and a pair of Zener diodes having identical characteristics. To do this, rectify an AC voltage with a rectifier diode and slightly pre-smooth it with a charging capacitor. Apparatus:-Experimental kit and patch cords. This heavy doping results in a low value of reverse breakdown voltage (BV R). Connections are made as shown in the circuit diagram. I-V Characteristics of Zener Diode Aim:- To study of the I-V characteristics of zener diode in Forward bias and Reverse bias conditions. 3. This breakdown voltage is known as the Zener voltage. In breakdown the voltage across the Zener diode is close to constant over a wide range of currents thus making it useful as a shunt voltage regulator. Connect the circuit as shown in figure (2). 17. ZENER DIODE CHARACTERISTICS . Current-voltage characteristic of a Zener diode with a breakdown voltage of 3.4 V. Temperature coefficient of Zener voltage against nominal Zener voltage. The voltage across the zener will remain steady at its break down voltage VZ for all the values of zener current IZ as long as the current remains in the break down region. What makes them different from other diodes is that Zener diodes will also allow current to flow in the reverse direction when the voltage is above a certain value. Plot the V-I graph and observe the change. The maximum reverse current is limited, however, by the wattage rating of the diode. The Zener breakdown voltage is the minimum reverse biased voltage below which the diode blocks the reverse … In Experiment A, a 12V zener diode is connected in reversed biased as shown in the image and it can be seen that the zener diode blocked the voltage effectively because it was less/equal to the breakdown voltage of the particular zener diode and the lamp thus stayed off. Experiment No: 1 Diode Characteristics Objective: To study and verify the functionality of a) ... the corresponding readings V r and I r. 3. It is generally 0.6v for a Silicon diode. Select the Zener diode from the drop down list. On plotting an V vs I curve, we will get a clear picture of the ... we just reverse the diode to measure the I-V characteristics, the sudden change might destroy the diode. Zener diode experiment. Plot the graph between VS and VO taking VS on X-axis and VO on Y-axis. EXP-7> To draw characteristics of a zener diode and to determine its reverse breakdown voltage. This may lead to ... ZENER DIODE CHARACTERISTICS AIM: 1. Figure . We will then plot it to get the depen-dence. 8. Forward biasing will cause a large I F with a rather small value of V F.Reverse biasing will generally not cause current conduction until … The forward bias region of a Zener diode is identical to that of a regular diode. Similarly, experiment by keeping the diode in forwarding bias and tabulate the readings. Forward (drive) current can have a range from 200 uA to 200 A, with the most common forward (drive) current being 10 mA or 200 mA. 1-3 2. Ans: The breakdown voltage of a diode is the minimum reverse voltage to make the diode conduct in reverse. This article will help to explain the characteristics which make up zener diodes, specifically how the voltage across a zener diode varies with the current flowing through it. Zener Diode Characteristics. All Study Guide At One Place Physics Practical Class 12. Voltage (V. 3) Temperature Coefficient Zener Impedance (R2 . When this occurs there is a sharp increase in reverse current. Zener diodes are semiconductor PN junction diodes with controlled reverse-bias properties, which make them extremely useful as voltage references. Plot Volt-Ampere Characteristics of Zener Diode. The experiment is continued till the milliammeter shows a large deflection while the voltmeter reading remains a constant, indicating the break down voltage. Answer: c Explanation: Zener diodes are used as voltage regulators but they aren’t called voltage regulators. Vary supply voltage (Vs) in in steps of 1volt from 0 - 15 volts and note the corresponding Zener Current (IZ), Load Current (IL) and Output Voltage (VO). Diodes . This voltage is … Theory: A Zener Diode is constructed for operation in the reverse breakdown re-gion.The relation between I-V is almost linear in this case Vz =Vz0+Iz Rz, In reverse bias, the minority charge carrier current flows through junction. Applying a reverse bias causes a strong electric field get applied across the device. This property of zener diode makes its use as a voltage regulator. Thus it acts as a voltage regulator. For Zener diodes, silicon is preferred to Ge because of its high temperature and current capability. The following contains the verified lab manual record of the experiment for reference along with the readings. VDC +2 . The reverse breakdown voltage of the Zener diode, V = ………….V. zener diode. The breakdown voltage is specified as a voltage with a tolerance, such as 10 volts ±5%, which means the breakdown voltage (or operating voltage) will be between 9.5 volts and 10.5 volts. Zener Diode Definition Zener Diode Working Zener Diode Circuit Symbol VI Characteristics of Zener Diode Zener Diode Applications FAQs. What is the differences between the PN junction diode and Zener diode fabrication? Ans:Zener diode is generally used in Reverse biased condition.When zener diode is forward biased,it acts as a normal P-N junction diode. If a zener diode reads a voltage near its rated zener voltage, VZ, then it is good. calculate static and dynamic resistance in both forward and reverse bias condition. First identify the terminals of Zener diode, there will be a black colored circular band on one side of the Zener diode. 18. Because of technological limitations, the "ceramic" capacitors that you have been using up to now do not have sufficiently high capacitance to be used in this application. Q9: Is the zener diode an effective limiter? Then we will see how that experiment can be performed using the PSLab Android App and the PSLab Hardware Device. Avalanche breakdown voltage may vary but Zener breakdown voltage is constant. This post includes explanation of operation of Zener diode and V-I Characteristics of Zener Diode. It is read as n-type of Zener diode and the other as p-type. Then for all other combinations of input voltage and load current the Zener diode conducts the excess current thus maintaining a constant voltage across the load. ... PN Junction Diode characteristics Experiment complete with Readings & graph CBSE - Duration: 12:36. Do the same experiment by connecting the Zener diode in the forward bias. The break down voltage Vz is obtained from the graph as shown below. We just reverse the diode to measure the i v characteristics the sudden change might destroy the diode. Developed by Amrita Vishwa Vidyapeetham & CDAC Mumbai. Ans: Avalanche breakdown and Zener breakdown. 19. The characteristics of a regular junction diode will show that it is designed primarily for operation in the forward direction. Any kind of infringement will lead to legal action. Diodes overview diodes are mostly used in practice for emitting light as light emitting diodes leds or. Unlike ordinary PN junction diode, the reverse current in Zener diode is measured using milli-ammeter due to the large flow of current. Connect the CRO CH1 across the input and CH2 across resistor. analyze the working of Zener diode as a voltage regulator for line regulation and load regulation. This article will help to explain the characteristics which make up zener diodes, specifically how the voltage across a zener diode varies with the current flowing through it. 10. block of Figure 1. Zener diodes not only stabilize long-term voltage fluctuations, but also short-term fluctuations as they are caused by the residual ripple of a rectified, pre-smoothed AC voltage. To Study the Reverse characteristics of Zener diode. This value can be controlled during manufacture. lN940B . 22. 2. Compare Zener Breakdown and Avalanche breakdown? The first quadrant is the forward biased region. 2. To Study the working of a diode as half w ave rectifier with and without filter. A signal diode or rectifier has the forward voltage specified as a max voltage at one or more current levels. To see the circuit diagram, click on the 'Show/hide circuit diagram' check box seen inside the simulator window. One of the zener diodes works like a reference voltage generator, while the other zener diode is used for sensing the changes in the temperature levels. EXPERIMENT: DIODE & ZENER DIODE Objective:- To study the forward and reverse bias characteristics of diode and zener diode. Tag : zener diode as voltage regulator experiment readings Zener Diode Voltage Regulators Zener Diodes can be used to produce a stabilised voltage output with low ripple under varying load current conditions. However, the Zener Diode or Breakdown Diode, as they are sometimes referred too, are basically the same as the standard PN junction diode but they are specially designed to have a low and specified Reverse Breakdown Voltage which takes advantage of any reverse voltage applied to it. What is the difference between p-n Junction diode and zener diode? Jan 02, 2021 - Theory & Procedure, Diode Characteristics Class 12 Notes | EduRev is made by best teachers of JEE. The range of values goes from a few Volts up to about 200 Volts. Brief Theory: When a reverse-bias voltage is applied to a pn junction, the electric field in the space-charge region is increases. It is a semiconductor diode, in which the n-type and the p-type sections are heavily doped, i.e., they have more percentage of impurity atoms. The device, because of one P-N junction, is quite similar to a diode but it differs from an ordinary diode as it has three terminals. हिंदी Tabulate different reverse currents obtained for different reverse voltages. Characteristics. Observations: Table: 1 Forward Bias Condition: analyze the forward and reverse bias characteristics of Zener diode. 9. Add a 9V zener diode in parallel with the - kΩ load resistance in Figure 9 and repeat the 2-measurements in step 7. The forward bias characteristic of Zener diode is same as the normal PN junction diode but in reverse bias it has different characteristic. 3. Zener diodes are a special kind of diode which permits current to flow in the forward direction. Aim : To study the VI Characteristics of Zener Diode. This is to compensate for the damage that occurs in the case of a pn junction diode when the reverse bias exceeds the breakdown voltage and thereby . Connect voltmeter and ammeter in correct polarities as shown in the circuit diagram. Give the input as triangular voltage waveform from Function Generator (both positive and negative peaks). Tabulate different reverse currents obtained for different reverse voltages. mA . By adjusting the rheostat, voltmeter reading is increased from 0 and in each time note the corresponding reading in milliammeter. Zener Diode Characteristics. Write the features of UJT. This document is highly rated by JEE students and has been viewed 162 times. The V-I characteristics of an ideal zener diode is shown in Figure 1–1 (a) and a simple regulator circuit based on it in Figure 1-1 (b). The process becomes cumulative and leads to the generation of a large number of charge carriers resulting in Avalanche Breakdown. Zener Diode Characteristics Part A: V-I Characteristics Part B: Zener Diode act as a Voltage Regulator 3. To observe and draw the V-I characteristics and Regulation characteristics of a Zener diode. ELE 213 - Electronics Page 1 of 5 Lab #2 Experiment procedure A. Bridge Rectifier Circuit 1. The resistor is selected so that when the input voltage is at VIN(min) and the load current is at IL(max) that the current through the Zener diode is at least Iz(min). മലയാളം We are going to take Zener I-V Characteristics Curve experiment as an example to understand how we can perform a general experiment using the PSLab device. To draw the characteristic curve of a Zener diode and to determine its reverse breakdown voltage. A Zener diode not only allows current to flow from anode to cathode but also, in the reverse direction on reaching the Zener voltage. When the diode is in the reverse bias condition, the width of the depletion region is more. As a result, the bond breaks and electron hole pairs are generated. Zener diode characteristics can be observed. 20. The experiment is continued till the milliammeter shows a large deflection while the voltmeter reading remains a constant, indicating the break down voltage. Give the input as triangular voltage waveform from Function Generator (both positive and negative peaks). Better schemes use a device called a Zener diode. It permits current to flow in the forward direction as normal, but will also allow it to flow in the reverse direction when the voltage is above a certain value - the breakdown voltage known as the Zener voltage. Physics Investigatory To Study V I Characteristics Of Zener . While doing the experiment do not exceed the ratings of the diode. Observe the nearly constant voltage in the breakdown region. Plot the V-I graph and observe the change. Ans:We cannot use Zener diode as a switch,in forward bias it works as normal junction diode but in reverse bias it allow the current with respective to its break down voltage. They provide a low-cost and no frill method for voltage regulation. 3. ... Zener diode is a P-N junction diode specially designed to operate in … So we take the ohmmeter and place it across the leads of the diode. Fig 2: Zener diode characteristic curve . Give the input as triangular voltage waveform from Function Generator (both positive and negative peaks). Diode characteristics experiment readings. Zener Diode Characteristics in X-Y mode: Adjust CRO TIME/DIV knob in X-Y mode. Find Zener Breakdown Voltage in Reverse Biased conditions. The reverse characteristic curve of the Zener diode is obtained. Basically there are two type of regulations such as: Fig (3) - Circuit Diagram of Zener Diode as Line Regulator: Fig (4) - Circuit Diagram of Zener Diode as Load Regulator: c) Zener Diode as Line Regulator (for variations in supply voltage): Connect the circuit for Line regulation as shown in figure (3). The breakdown voltage or zener voltage (VZ) across the diode remains relatively constant. The function of a regulator is to provide a constant output voltage to a load connected in parallel with it in spite of the ripples in the supply voltage or the variation in the load current and the zener diode will continue to regulate the voltage until the diodes current falls below the minimum IZ(min) value in the reverse breakdown region. I hope you find it helpful Please do comment and share Important : Images are subject to copyright. Not Specified Not Specified The function of CR1 is to provide additional regulation of the input voltage and form the basis of the reference output. Take the readings and note Voltmeter reading across Zener diode and Ammeter reading. To plot Volt-Ampere characteristics of Zener diode. 4. For correct voltage regulation, we need to find out precisely what voltage should be across the Zener diode.Zener breakdown voltage should be approximately close to the desired voltage we want. Viva questions: 1. Result: a. When the reverse bias voltage is greater than a predetermined voltage then the Zener … To Study the V-I characteristics of Forwa rd Biased PN junction diode. The reverse breakdown voltage varies between different Zener diodes. They have a large forward current flowing through them with a negligible voltage drop across them. You can notice the corresponding ammeter and voltmeter readings. current increases at a rapid rate. Calculate static and dynamic resistance of the Zener diode in both forward and reverse biased conditions (before, after break down voltages). We are going to learn about an experiment to find out the Zener breakdown voltage and draw the characteristics of Zener diode.Why should we do this experiment? Identification, Specification & Testing of Components and Equipment’s, Forward & Reverse Bias Characteristics of PN Junction Diode, Half Wave Rectifier With and Without Filters, Full Wave Rectifier With and Without Filters, Input & Output Characteristics of CB Configuration and h-Parameter Calculations, Input & Output Characteristics of CE Configuration and h-Parameter Calculations, Frequency Response of Common Emitter Amplifier, Uni Junction Transistor(UJT) Characteristics, Silicon-Controlled Rectifier (SCR) Characteristics, Characterstics of Emitter Follower Circuit, Design and Verification of Fixed Bias Circuits. Initially, a negligible constant current flow through the zener diode in its reverse bias but at certain voltage, the current becomes abruptly large. Ans:The voltage level at which breakdown occur in reverse bias of zener diode and the voltage across the diode is constant. Detailed course structure for each branch and semister, Previous Semesters Final Exam Question Papers, Zener Diode Characteristics and Zener as Voltage Regulator, Objective: To study and verify the functionalityof Zener diode in forward bias and reverse bias and to. To Study the working of a diode as Bri dge rectifier with and without filter. In the forward bias direction, the zener diode behaves like an ordinary silicon diode. To Draw The Characteristic Curve Of A Zener Diode And To. The Zener diode mainly operates in reverse biased condition. Ans: A voltage regulator is an electronic circuit that provides a stable dc voltage independent of the load current, temperature and ac line voltage variations.
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