Zener diode characteristics zener regulator prelab. Characteristics in chapter 1 understanding the pn junction, we have seen how a pn junction is formed from a ptype and ntype semiconductor. The properties of a pn junction are very dependable. Experiment 16 the pn junction university college dublin.
The iv characteristics curve of a zener diode, shown below, is the curve which shows the currentvoltage relationship of a zener diode. The values of v ak and i ak are noted down, plotted and scr forward resistance is found. Vi characteristics of pn junction diode electronics post. The graph showing the forward bias voltage and forward current is known as the forward characteristics, and that showing the reverse bias voltage and reverse current is known as the reverse characteristics. Working of pn junction diode with biasing, characteristics. It arises from the fact that the forward characteristics of real pn. Zener effect dominates at reverse voltages less than 5 volt whereas avalanche effect dominates above 5 v. Photo diode operationvi characteristics ece tutorials. Diodes and diode circuits tlt8016 basic analog circuits 20052006 2 3. When a section of ptype material and a section of ntype material are brought in contact to form a pn junction, a number of interesting properties arise. A pn junction is known as a semiconductor or crystal diode, so called because pn junction is grown out of a crystal. The reverse breakdown of a pn junction may occur either due to zener effect or avalanche effect. A zener diode, a power supply with potential divider, resistance of 125 ohm, a milliammeter, a voltmeter, connecting wires.
The circuit diagram to plot the vi characteristics of a zener diode is shown. Diodes are mostly used in practice for emitting light as light emitting diodes, leds or controlling voltages in various circuits. A photo diode is always operated in reverse bias mode. Let vcc be the dc voltage source to be used in the experiment.
This causes electrons from nregion to get attracted to positive terminal of the battery and holes by the negative terminal. To study the reverse bias characteristic of photodiode for different intensity of incident light on it. The vi characteristics of a diode can be forward or reverse. To investigate basic powersupplies concepts such as rectification, filtering, and regulation. Experiment no 1 pn junction diode characteristics youtube.
If you find these terms foreign, just read the chapter about understanding the pn junction. Instead, a diode will have negligible resistance in one direction to allow current flow, and a very high resistance in the reverse direction to prevent current flow. We use zener diodes for voltage regulation and voltage stabilisation. When the photodiode is forward biased, there is an exponential increase in the current. In this experiment, we try to observe the relation between the voltage and corressponding current generated. We try to see the voltagecurrent realtion in diodes by applying a voltage across it and measuring the corressponding current. The diode iv sweep lab is designed as a laboratory or athome experiment. 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. Today we will continue studying these important devices by measuring the current characteristics under various light conditions the diagram on the next slide shows a. This potential difference can alter the flow of majority carriers, so that the pn junction can be used as an opportunity for the diffusion of electrons and holes. Experiment 4 characteristics of a silicon diode and the zener diode introduction the diode is a device formed from a junction of ntype and ptype semiconductor material. All the initial answers to the questions of the assignment i. In nonfully depleted photodiodes, however, all three factors contribute to the response time.
The ideal diode has zero resistance for the forward bias polarity, and infinite resistance conducts zero current. Photodiode, voltmeter 010volt, miliammeter, variable dc source010 volt, wiresleads. Experiment 16 the pn junction introduction in this experiment on the physics of the pn junction, a determination is made of both the universal constant ek i. To verify the vi characteristics of pn junction diode and zener diode. Clampers are easily distinguished from clippers in that they include a capacitive element. Diode characteristics 2012 summary this experiment was set up to investigate the different properties and characteristics of several different types of diode. Definition, symbol, and types of diodes electrical4u. Basic electronics notes on vi characteristics of zener.
Pn junctions consist of two semiconductor regions of opposite type. We have also learned about diffusion current, depletion region, drift current and barrier potential. Replace the procedure in experiment 3 with the following procedure 1 measure the voltage and current through a signal diode use a 1n4148 from your graymark kit these are also available in the instrument room. For zero luminance the photo current is almost zero except for small dark current. Repeat the above procedure for the forward and reverse characteristics of scr for a gate current i g i g2. Definition ptype semiconductor is suitably joined to ntype semiconductor,to conduct surface is called pn junction. To draw the characteristic curve of a zener diode and to determine its reverse breakdown voltage. The pn junction is a versatile element, which can be used as a. Iv characteristics pn junction diode reverse biasing a pn junction when the polarity of the battery is reversed, the cathode is connected to positive end of the battery and anode to negative.
A simple solar cell experiment the following experiment was performed using a commercial polycrystalline silicon solar cell with an active area of 8. To study and verify the functionality of a pn junction diode in forward bias. Gunn diode or ted transferredelectron device type of the semiconductor or vacuum form of diode, which is designed to operate in the range of microwave frequencies from single ghz to single thz. An experiment to measure the ivcharacteristics of a. The critical parameter of this type of diodes is the zener breakdown voltage. Photodiode characteristics silicon photodiodes are semiconductor devices responsive to highenergy particles and photons. The principle behind the diode is similar to a valve or a gate. The experiments in this laboratory exercise will provide an introduction to. Gunn diode tips definition, characteristic and applications. Zener diode, power supply, dc milliammeter and dc voltmeter. It is a silicon or germanium pn junction diode which is photosensitive in. Photodiode characteristics and applications photodiode. A typical damper will include a capacitor, diode, and resistor with some also having a dc battery.
Such junctions show a pronounced rectifying behavior. They are also called pn diodes in analogy with vacuum diodes. Gunn as a first person has observed that in the wafers of gallium arsenide with a very small. Principle behind the invention of the diode the very basic principle that paved way for invention is the unidirectional way of flow of current.
Zener diode is a reversebiased heavilydoped pn junction diode which operates in the breakdown region. Performance of dc motors experiment 2 karimi lordramza. The forward characteristics of a diode is non linear. Each diode was investigated by plotting the iv curve using a precision sourcemeasurement unit b2902a and a laptop with the corresponding quick iv measurement software installed. Diode applications experiment 5 linkedin slideshare. Photodiodes operate by absorption of photons or charged particles and generate a flow of current in an ex. To plot the characteristic curves for the zener diode and hence to determine knee and breakdown voltage. A pn junction is the metallurgical boundary between the n and pregions of a semiconductor crystal.
To study and verify the functionality of a pn junction diode in forward bias b pointcontact diode 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. These include generic diode, schotty diode, shockley diode, constantcurrent diode, zener diode, light emitting diode, photodiode, tunnel diode, varactor, vacuum tube, laser diode, pin diode, peltier diode, gunn diode, and so on. The zener diode mainly operates in reverse biased condition. Normally the voltage is taken along the xaxis and current along yaxis. A zener diode is a special kind of 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. Experiment 6, photodiode and phototransistor current.
Voltampere vi characteristics of a pn junction or semiconductor diode is the curve between voltage across the junction and the current through the circuit. In forward bias condition, current is constant until certain voltage is reached. We have seen in a previous experiment that the resistance of both a photodiode and a phototransistor changes as the intensity of the light hitting the device varies. A theoretical model of the diode characteristic curve is given by the equation. From the photo diode characteristics it is seen clearly that the photo current is almost independent of applied reverse bias voltage. Electrons and holes diffuse from areas of high concentration toward areas of low concentration. This article discusses about pn junction diode, diode theory of zero bias, forward bias, reverse bias with vi characteristics and its applications. Although in the real world, diodes can not achieve zero or infinite resistance. Each work group will submit a report due one week after the laboratory experiment which should include the following sections. Zener doide is a special diode with increased amounts of doping. Lab experiment related theory available in following books. A pnjunction diode is formed when a ptype semiconductor is fused to an ntype semiconductor creating a potential barrier voltage across the diode junction the effect described in the previous tutorial is achieved without any external voltage being applied to the actual pn junction resulting in the junction being in a state of equilibrium.
Research the names for these parameters and values you can expect for them. Pdf this paper describes an experiment that studies the effect of diode temperature. To characterize a rectifier diode and a zener diode. To plot voltampere characteristics of silicon pn junction diode. While doing the experiment do not exceed the ratings of the diode. The currentvoltage sweep is one of the fundamental experiments used to characterize the behavior of a diode. You may use either of three methods to measure the vi characteristics. The very first diode by sir thomas alva edison was a light bulb with certain modifications on it. Pn junction diode baising and its vi characteristics elprocus.
Vz0 is the voltage at which the straightline approximation of the iv characteristic intersects the horizontal axis. You diodes will use the bit bucket breadboarding system to build and test several dc and ac diode circuits. Diodes overview diodes are mostly used in practice for emitting light as light emitting diodes, leds or controlling voltages in various circuits. Photodiode characteristics n iv characteristics the currentvoltage characteristic of a photodiode with no incident light is similar to a rectifying diode. To get familiar with working knowledge of the following instruments. Low cost national instruments data acquisition products are used to excite and acquire data from the dioderesistor network. The diodes are classified into different types based on their working principles and characteristics. Working of pn junction diode if an external potential is applied to the terminals of pn junction, it will alter the potential between the p and nregions.
To analyze the input and output characteristics and to. An experiment to profile the voltage, current and temperature behaviour of a pn diode. Plot forward and reverse characteristics using the abovetabulated values. The lead connected to the ptype material is called the anode and the lead connected to the ntype material is the cathode. To find cutin voltage for silicon pn junction diode. They provide a lowcost and no frill method for voltage regulation. A diode is effectively like a valve for an electrical circuit semiconductor diodes are the most common type of diode. Measure and plot vi characteristics of zener diodes. The zener breakdown voltage is the minimum reverse biased voltage below which the diode. Diode iv characteristics contents that should be delivered for every report. Pdf an experiment to profile the voltage, current and temperature.1019 1031 59 173 1485 1257 1132 1357 25 456 1175 699 1217 1351 1166 736 1500 1057 1393 1429 47 315 216 174 1341 122 621 333 919 297 1397 1046 503 390