Oscilloscope 4. Medium. Experiment No: 1 Diode Characteristics Objective: To study and verify the functionality of a) PN junction diode in forward bias b) Point-Contact diode in reverse bias Components/ Equipments Required: Components Equipments Sl.No. This was also to e xpand the student’s knowledge and as well as his laboratory skills on the subject. Planck’s Constant Viva Questions: Planck’s Constant using LED [determination of Planck’s constant by using light-emitting diodes (LEDs)] APPARATUS: Planck’s constant kit, wires, graph paper, and 3-4 LEDs. Diodes are designed such that the potential difference across it needs to be at a minimum of 0.6 V before any current can pass through it. Most of the commercial LEDs are realized using a highly doped n and a p Junction. Arrange the sliding contact of the rheostat to minimum. Repeat these measurements of the I–V curves for each of the other diodes, noting that 5 of them have a maximum current rating of 20mA and the IR LED has a 100mA rating. through a component (eg a filament lamp) can be measured and the results plotted on a graph to show the I-V characteristic of the component. Equipment needed Current-voltage (I-V) characteristics for components. their I-V characteristics are very different. FORMULA USED: Planck’s constant is h = eV /ν, where e is an electronic charge, V is voltage reading in voltmeter, v is the frequency of particular LED color. The near-linear light output characteristic of an LED is exploited in small length fiber optic analog communication links, such as fiber optic closed-circuit TV. Sorry, your blog cannot share posts by email. This was conducted as an introductory to Electronics laboratory and in line with some topics in lecture classes. What are the electrical characteristics of LEDs? A light-emitting diode is a p-n junction rectifier. Electromotive Force and Potential Difference, 4. 1N4148 diode (x 1) 2. Le Conditionnement Évaluatif : un effet polymorphe interprété au sein d’une approche intégrative à multiples processus Characteristics of Light Emitting Diode (LED) Aim of experiment In this experiment, we study and measure the P-I characteristics of Light Emitting Diode (LED), which used in optical fiber communication as a light source. Compare the theoretical and practical values (cut-in voltage and resistances). The interaction of light and matter is synthetically expressed by Einstein-Planck equation: where the constant of proportionality hhas the following value: It represents a milestone in the introduction to quantum mechanics; also known as “quantum of energy” or “quantum of action”. cabraham. Nov 1, … and current were collected the following current-voltage graph can be drawn. Experiments Questions I Use an LED as a visual indicator of small currents (for example, cur-rent produced by a lemon cell).8 What are the conditions necessary for electric current to be in a circuit? DOCX, PDF, TXT or read online from Scribd, MONEY Master the Game: 7 Simple Steps to Financial Freedom, Battlefield of the Mind: Winning the Battle in Your Mind, The Go-Giver: A Little Story About a Powerful Business Idea, 88% found this document useful, Mark this document as useful, 13% found this document not useful, Mark this document as not useful, Save Plot V-I &amp; PI characteristics of LED.docx For Later, A Light Emitting Diode (LED) is a semiconductor diode mode by creation of, same way that we described the creation of permanent light radiation. Light Emitting Diode (LED) Schematic symbol and I-V Characteristics Curves showing the different colours available. This category provides structured courses for your A-Levels. Tunnel Diode VI Characteristics: As the forward voltage starts to increase, the diode current raises rapidly due to tunnel effect. Diodes and transistors are made from semiconducting materials: typically crystalline silicon. Five camouflage patterns were used (MARPAT Woodland, Desert, and Navy, and Arctic and Swiss Objective: The object of this experiment is to compare the I-V characteristics of a diode with those of a resistor.By measuring the voltage drop across the diode or resistor as the current is varied, the student will discover the relationship between the current and the voltage. 10M resistor (x 1) I. Diodes Overview Diodes are mostly used in practice for emitting light (as Light Emitting Diodes, LEDs) or controlling voltages in various circuits. The threshold voltage. Tabular column: Forward bias Reverse bias V D (volts) I D ( mA) V D (volts) I D ( µA) (b) Reverse Bias Condition: 1. characteristics of test LEDs in forward and reverse bias, respectively. A light-emitting diode (LED) is a semiconductor light source. 22u capacitor (x 1) 5. Diodes and pn Junctions. If you need to use your diode on another day, mark it with a piece of tape with your name and leave it in the storage cubbies in the back of the lab. This category provides structured courses for your GCSE's. Various Modes in V-I Characteristics of SCR. to current varying with the same pattern). The commercially used LED’s have a typical voltage drop between 1.5 Volt to 2.5 Volt or current between 10 to 50 milliamperes. characteristics of test LEDs in forward and reverse bias, respectively. Insert the key. LED Characteristics. They are graphical characteristics showing how the current (I) varies as the potential difference (V) across the component varies. Although it is possible to collect the data for this lab very quickly, it is The proper-ties of transistors will be studied in this module so basically the focus here is understanding how transis- tors work. LIGHT EMITTING DIODE CHARACTERISTICS (SAMPLE LAB WRITEUP) John A. McNeill ECE Box 000 March 17, 2004 ABSTRACT This lab investigates the V-I characteristic of a light-emitting diode (LED). CIRCUIT DIAGRAM: Fig 1.1(a) Circuit diagram for VI characteristics of SCR. AVO meter 5. If a set of results were taken whereby both positive and negative readings of p.d. The following helps to show this (but with limited detail): Post was not sent - check your email addresses! 8EI7. Optical fiber power meter 3. Electrical Power and Internal Resistance, 4. You should research how to read the value of resistors from the coloured rings on them. They have a non-linear resistance. An illumination-grade LED containing a single semiconducting element requires the same voltage, but operating currents are much higher, typically several hundred milliamperes. Wires 6. The final procedural section will use the LabVIEW program LED-Output.vi to measure the optical emission intensity of the LED as a function of the LED current. Apparatus 1. It consists of a PN Junction Diode and when voltage is applied to the LED, electrons and holes recombine in the PN Junction and release energy in the form of light (Photons). II a) Use an LED, a variable voltage source, and various resistors /po-tential dividers to measure LED’s I-V characteristic. An equation that models the I-V characteristic of a non-ideal diode is shown below. I – Current. Figure 2. AVO meter 5. LIST OF EXPERIMENTS OPTICAL EXPERIMENTS 1. When carriers are injected across a forward-biased junction, it emits incoherent light. V-I CHARACTERISTICS OF DIODE 7 • A general Comment on my Reverse bias data: We can see that the reverse bias is linear which is because the range of the voltage across the diode in which the data was taken falls just in the range of the linear part of the reverse bias curve. To determine holding, latching current and break over voltage of given SCR. Here, we are testing on junction diode, Zener diode, and light-emitting diode (L.E.D) which as we what we know, they are … ii) Junction Voltage vs. Current. 8EI7. CONCLUSION This experiment focuses on the investigation of the basic characteristics of a diode. LED I-V Characteristics Home. In this video , we are going to watch how to apply below practicalPractical Name - To measure the V-I Characteristic of LED (Light Emitting Diod) . Oscilloscope 4. The laser operation occurs at a p-n junction that is the boundary region between p-type and n-type materials. Hence the LED allows the flow of current in the forward direction and blocks the current in the reverse direction. The colour of eight emitted by an LED depends on its band-gap energy The intersity of eight emitted is determined by the forward current by the p-n junction. The following points are important to understand and note; An LED is a light emitting diode, the have very similar characteristics to standard diodes. SCR Characteristics . Experiment 2 involved outdoor measurements of LED visibility against camouflage patterns in natural daylight. III. The V-I characteristic of LED is given below: V-I Characteristics of PN Junction Diode. They are called active devices since transistors are capable of amplifying (or making larger) signals. A careful observation of the V-I characteristics reveal that an SCR has three basic mode of operation: Reverse Blocking Mode, Forward Blocking Mode and Forward Conduction Mode. exceed the 20 mA maximum current rating for this LED. : 4 -= + = 1 2 4. Diodes: Experiment Guide Components required for this lab: 1. stand for voltage-current characteristics of an electrical component or device Draw the V − I characteristies of an LED. 4. As LEDs’ colour is determined by the band gap 1 of the semiconductor and the forward voltage, \(V_F\), also varies with the material. To increase its conductivity, the silicon is normally "doped", i.e. D threshold D threshold v v D S if v v i I e th if v v D = < = ≥ 0 If v D is greater than v threshold, then the diode is said to be forward-biased or it is said to be in the forward-biased region. 5m multimode optical fiber . Single indicator LEDs require 2 to 4 volts of direct current, with current in the range from 1 to 50 milliamperes. However this can be corrected by using lenses and other optical devices. Now, gently move the rheostat contact to provide a positive bias voltage. When p- and n-type semiconductors are brought together to form a p-n junction, electrons with energies in the conduction band diffuse from the n-side to the p-side and holes with energies in the valence band diffuse from the p-side to the n-side. The lead connected to the p-type material is called the Figure 2 shows the characteristic curve of a LED. The relationship between current through, and voltage across, a component is called the current-voltage (I-V) characteristic. 4. I-V Characteristics of a Diode vs. a Resistor. Now, gently move the rheostat contact to provide a positive bias voltage. In this video , we are going to watch how to apply below practical Practical Name - To measure the V-I Characteristic of LED (Light Emitting Diod) . Aim We try to see the Voltage-Current realtion in Diodes and compare the difference between various types of diodes including Zener Diode. Forward bias of approximately 1 volt is needed to give significant forward current. FORMULA USED: Planck’s constant is h = eV /ν, where e is an electronic charge, V is voltage reading in voltmeter, v is the frequency of particular LED color. 1M resistor (x 1) 4. 1. study of cro 3 2. v-i characteristics of pn junction diode 10 3. v-i characteristics of zener diode and zener regulator 16 characteristics 4. v-i characteristics of led 21 9 Experiment No. They may be regarded as one-way valves and they are used in various circuits, The V-I curve is practically applicable in burglar alarms. Optical fiber power meter 3. Zener Diode Characteristics Part A: V-I Characteristics Part B: Zener Diode act as a Voltage Regulator 3. Another parameter is the threshold voltage U*, this stress is extrapolated from the linear part of the VA characteristics (red in Figure 1).When this voltage is linearized to break in the dependence of current flowing in the diode voltage is applied to the LED. Einstein’s Equation and the Photoelectric Effect, To be able to describe an experiment to obtain the. Object: - Plot V-I and P-I Characteristics of (LED) Light Emitting Diode. This tutorial will help to study the trend of V-I characteristics of Light Emitting Diode. Apparatus 1. Experiment 1 involved controlled laboratory measurements of LED visibility against selected uniformly colored backgrounds. These camouflages represent a variety of … Figure 1: p-n+ Junction under Unbiased and biased conditions. These characteristics are also known as I–V curves, referring to the standard symbols for current and voltage. Reverse Blocking Mode . DATA ANALYSIS Plot graphs of current (ordinate) vs voltage (abscissa) for each LED. Background. Reactions: Austin Clark. Light Emitting Diodes (LEDs) will burn out if you hook them directly to the 5V power supply without a current limiting resistor. Link: Interactive Java Tutorial: Light emitting diodes. However this is the purpose of a diode, they only allow current to flow in one direction. It is one of the fundamental physics constants, useful to understand the meaning of quantization in the atomic and nuclear world and represents the fundamental unit of action for discrete atomic scale system; it defines … There are different types of light-emitting diodes are available in the market and there are different LED characteristics which include the color light, or wavelength radiation, light intensity. LED I-V characteristics An LED is a light emitting diode, the have very similar characteristics to standard diodes. Experiment 4. Between 0 and 0.6 V: The resistance is extremely high (infinite), so no current can flow (, 0.6 V – 0.7 V (approximately): The resistance decreases, the current can increase     (, 0.7 V and upwards: The resistance decreases further, the current increases even more (, With any negative p.d: The resistance is extremely high (infinite), so no current can flow (. 5. across and the current. state two advantages of LED lamps over conventional incandescent lamps. A key point to note however is that the threshold voltage (the minimum voltage required for a current to flow) varies depending on the colour (this will become more apparent when studying quantum physics later in the year). Like a normal diode, the LED consists of a chip of semiconducting material doped with impurities to create a p-n junction. list of experiments page no. In electronic components with more than two terminals, such as vacuum tubes and transistors, the current-voltage relationship at one pair of terminals may depend on the current or voltage on a third terminal. V – LED forward bias voltage. CONCLUSION This experiment focuses on the investigation of the basic characteristics of a diode. General Electronics Chat LED I-V Characteristics. Conduct the experiment for obtaining the forward bias VI characteristics of the given diode.if the cut in voltage is .3V,it is Germanium diode.If it … 2 Resistor (1K ) 1(One) No. EXPERIMENT 6:Observation of the V-I characteristic of a diode Debangshu Mukherjee BS.c Physics,1st Year Chennai Mathematical Institute 31.10.2008 1 Aim of experiment We try to see the Voltage-Current realtion in Diodes by applying a voltage across it and measuring the corressponding current flowing through it 2 Apparatus required a)A diode The final procedural section will use the LabVIEW program LED-Output.vi to measure the optical emission intensity of the LED as a function of the LED current. Pure silicon has few free electrons and is quite resistive. 1k resistor (x 1) 3. V supply – Supply Voltage. The junction voltage vs. current characteristic of an LED is similar to the V-I characteristics of diodes. Thread starter Hurt ... but they still have resistance to a DC current flow and dissipate power as determined by V * I at their operating point. To be able to describe the uses and benefits of using light-emitting diodes (LEDs). This was conducted as an introductory to Electronics laboratory and in line with some topics in lecture classes. white, amber, and blue). at  0 V, any increase in p.d. LIST OF EXPERIMENTS 1. The forward bias Voltage-Current (V-I) curve and the output characteristics curve is shown in the figure above. Theory:-A Semiconductor diode is prepared by joining P and N sections of a semi conducting material like germanium or silicon. 4. Theory The diode is a device formed from a junction of n-type and p-type semi-conductor material. The second figure is used to represent a radiant power-forward current curve. LEDs are not capable of providing divergence below a few degrees. Diode characteristics Experiment Questions: 1.Experimently find out whether the given diode is made of Germanium or Silicon. The junction voltage vs. current characteristic of an LED is similar to the V-I characteristics of diodes. The tolerance … Typical IV curves for various colours of LEDs. A laser diode, like many other semiconductor devices, is formed by doping a very thin layer on the surface of a crystal wafer. The junction voltage vs. current characteristic of an LED is similar to the V-I characteristics of diodes. Insert the key. Date Name of the Experiment Remarks . Planck’s Constant Viva Questions: Planck’s Constant using LED [determination of Planck’s constant by using light-emitting diodes (LEDs)] APPARATUS: Planck’s constant kit, wires, graph paper, and 3-4 LEDs. Characteristics of Light Emitting Diode (LED) Aim of experiment In this experiment, we study and measure the P-I characteristics of Light Emitting Diode (LED), which used in optical fiber communication as a light source. VBO = Forward break over voltage VBR = Reverse break … The near-linear light output characteristic of an LED is exploited in small length fiber optic analog communication links, such as fiber optic closed-circuit TV. Identification, Specifications, Testing of R, L, C Components (Color Codes), Potentiometers, Coils, Gang Condensers, Relays, Bread Boards. DC Characteristics of LED and PIN Photo diode ... 8 V-I Characteristics of Gunn Oscillator 9 Mode Characteristics Of Reflex Klystron 10 Wavelength & Frequency Measurement 11 ... DC CHARACTERISTICS OF LED R. 2 :. EXPERIMENT: DIODE & ZENER DIODE Objective:- To study the forward and reverse bias characteristics of diode and zener diode. To determine the value of Vg is necessary to make a linear fit of the linear part of the curve and calculate the point where this line intercepts the x-axis. LED Characteristics. Note the voltmeter and milli ammeter readings. Static resistance is the order of 10 to 100 Ω, the dynamic resistance is < 1 Ω.. LEDs must have a resistor in series to limit the current to a safe value. Digital … After the point V V, the tunnel diode behaves as a normal diode. Theory: Diode lasers have been called “wonderful little devices.” They are small and efficient. Repeat the process by increasing the forward current in equal steps by changing the rheostat slider. If the variable resistor is altered so as to change the overall resistance in the circuit, both the voltmeter and ammeter readings will also change. In 1962, Nick Holonyak has come up with an idea of light emitting diode, and he was working for the general electric company. I - V characteristics of LED. However, there is one major difference. increases across it the greater the temperature becomes resulting in increased vibrations of the lattice ions, this in term reduces the magnitude of the rise in current. Like Reply. RESISTOR COLOR CODE To read them, hold the resistor such that the tolerance band is on your right. Experiment No. Alternatively w can say, that the external energy provided by V excites electrons at the conduction band to the valence, It consists of an encapsulated chip of semiconduct, ) with integrated optical components to shape its radiation p, Construct the equipment as shown in the figure, Set the bias selection switch in forward bias position,  Now set bias control Pot in particular level(-0.6), Increases the voltage applied to diode gradually in steps and note the ammeter and,  Now find the current flowing through photodiode by using below formula, Plot the graph between voltage across power, Set the bias selection switch in reverse bias position,  Now step by step increase the bias control voltage in 1.28V to 5V,  Note down voltage across photo diode VPD and voltage across resistor V. Plot the graph between voltage across photodiode VPD and current. Let us now discuss each of the three modes one by one. LEDs for Lighting Applications edited by Patrick Mottier –. Rectifiers (without and with c-filter) Part A: Half-wave Rectifier Optical Fiber Communication Experiment Kit 2. Forward V-I Characteristics : Connections are made as per the connection diagram. Object: - Plot V-I and P-I Characteristics of (LED) Light Emitting Diode. Typical data is displayed in Fig.3. R series = (V supply – V)/I. Experiment 1 involved controlled laboratory measurements of LED visibility against selected uniformly colored backgrounds. The relationship between current through, and voltage across, a component is called the current-voltage (I-V) characteristic. 10. drain and transfer characteristics of jfet 54 11. frequency response of ce amplifier 59 12. frequency response of cs fet amplifier 62 13. comparison of performance of self bias and fixed bias 66 circuits(new experiment) 14. applications of diodes (new experiment) 71 15. characteristics of thermistor 74 Hardware Design. ii) Junction Voltage vs. Current. Plot the V-I characteristics and calculate the resistance levels 5. Arrange the sliding contact of the rheostat to minimum. The current is always plotted on the y-axis of a graph and the p.d. Apparatus: LED Trainer module with bread board, 1K Resistor, Voltmeter, Ammeter Theory: - A Light Emitting Diode (LED) is a semiconductor diode mode by creation of junction of n type and p type material. With as the p.d. APPARATUS REQUIRED: Trainer kit, Patch cards, Multimeters. What is Ohmic? After the point V P, the tunnel effect is reduced and current flow starts to decrease even though increase in voltage( ie negative resistance region). Diodes appear peculiar components and often confuse students when first experimenting with them, due to the 0 V and 0 A readings shown with the current in one direction. The Light emitting diode is a two-lead semiconductor light source. This is contrasted with commercial ruby lasers with divergences of 0.2 degrees or less. on the x-axis. When the experiment was later tried the MicroAmmeter did not work Note the voltmeter and milli ammeter readings. THEORY A diode allows electricity to flow in one direction only and blocks the flow in the opposite direction. With low p.d’s, e.g. • LEDs do not approximate a "point source" of light, so they cannot be used in applications needing a highly collimated beam. A key point to note however is that the threshold voltage (the minimum voltage required for a current to flow) varies depending on the colour (this will become more apparent when studying quantum physics later in the year). results in a large increase in current, with a greater p.d, an increase results in a smaller rise in current. : Connections are made as per the connection diagram student’s knowledge and as well as his skills... Conductivity, the LED is similar to the V-I curve is shown in the previous page when introducing ’! Use an LED is similar to the barrier potential of the diode a non-ideal diode shown. Plotted on the subject this was also to e xpand the student s. Plastic case around a LED chip does not always indicate the color of the characteristics... Incoherent Light the theoretical and practical values ( cut-in voltage and resistances ) point V V, the have similar. Contact to provide a positive bias voltage Rectifier ) is the LIST of EXPERIMENTS OPTICAL EXPERIMENTS 1,... Pure silicon has few free electrons and is quite resistive resistance is order. Symbol and I-V characteristics Curves showing the different colours available is contrasted with commercial lasers.: Zener diode characteristics Part a: V-I characteristics Part B: Zener diode the previous page when introducing ’. This makes sense as Ohm ’ s equation and the Photoelectric Effect, to be to! Emitted Light of LED lamps over conventional incandescent lamps now, gently move the rheostat contact to provide positive. Same type can have significantly different characteristics, use the same type can have significantly different characteristics, the... Shown below special type of diode and they have similar electrical characteristics of LED ( Light diode... Emitting diodes to give significant forward current in equal steps by changing rheostat. Code to read them, hold the resistor such that the tolerance band is on your right various /po-tential! They only allow current to a safe value Desert, and various resistors /po-tential dividers to measure LED’s characteristic... Rheostat contact to provide a positive bias voltage its conductivity, the silicon is normally `` ''! The dynamic resistance is < 1 Ω to provide a positive bias voltage current the. ( a ) use an LED is a combination of elements that are designed to ensure the characteristics! A few degrees supply voltage is 12V or less hundred milliamperes MARPAT Woodland,,... Larger ) signals is essentially a PN junction diode special type of diode and they have similar electrical of... Figure 2 shows the characteristic curve of a diode is made of germanium or silicon a Regulator. Point V V, the current to a safe value should research how to read value! P-Type semi-conductor material Mottier – hence the LED is given below: V-I of... 2 involved outdoor measurements of LED ( Light emitting diode 4 volts of direct,... Basics of LED, a component is v-i characteristics of led experiment the current-voltage ( I-V characteristic... Essentially a PN junction diode the previous page when introducing Ohm ’ law! Negative readings of p.d are called active devices since transistors are capable of amplifying ( or larger. Used LED’s have a resistor in series to limit the current to flow in the device realtion! To read the value of resistors from the coloured rings on them Regulator 3 potential difference V. ) 1 ( one ) No from a junction of n-type and p-type material. Led’S have a typical voltage drop depends on the investigation of the basic characteristics of diodes reverse break ( ). Variable voltage source, and Navy, and so on read the value of resistors the. Is made of germanium or silicon resistor color CODE to read them, the! The same type can have significantly different characteristics, use the same voltage, but operating currents are higher! Current ( ordinate ) vs voltage ( abscissa ) for each LED indicator require... The commercial LEDs are not capable of amplifying ( or making larger ) signals mentioned in the from... A forward-biased junction, it emits incoherent Light essentially a PN junction diode understanding transis-! Of an LED is a laser where the active medium is a laser where the active component in various like! Voltage drop between 1.5 Volt to 2.5 Volt or current between 10 to 100 Ω, silicon. The supply voltage is 12V or less is understanding how transis- tors work however this is purpose. Kω resistor is suitable for most LEDs if the supply voltage is 12V or.... Diodes and compare the difference between various types of diodes studied in this module basically. Doped n and a p junction LEDs for Lighting Applications edited by Mottier. Controlled Rectifier ) is a special type of diode and they have similar electrical characteristics of SCR ( controlled. Relationship between current through, and various resistors /po-tential dividers to measure LED’s I-V characteristic of an LED is to... Link: v-i characteristics of led experiment Java Tutorial: Light emitting diode, the tunnel behaves! Incoherent Light the point V V, the dynamic resistance is the order of 10 to 50.... When carriers are injected across a forward-biased junction, it emits incoherent Light series to limit the to. Two advantages of LED lamps over conventional incandescent lamps like a normal diode ( LEDs ) the LEDs... Curve and the Photoelectric Effect, to be able to describe an experiment to obtain V-I:! Not always indicate the color of the plastic case around a LED of results were taken whereby positive... Try to see the Voltage-Current realtion in diodes and compare the difference between types... Uses and benefits of using light-emitting diodes ( LEDs ) showing how the current ( ). Resistor in series to limit the current ( ordinate ) vs voltage ( abscissa ) each! Optical devices characteristics an LED, a component is called the current-voltage ( I-V ) characteristic quadrant of rheostat! The coloured rings on them n-type and p-type semi-conductor material a two-lead semiconductor source. Proper-Ties of transistors will be studied in this module so basically the focus here is understanding how transis- tors.! The Light emitting diode ( LED ) Light emitting diode is shown in the graph above three. Experiment 2 involved outdoor measurements of LED visibility against camouflage patterns were used ( MARPAT Woodland,,. Component is called the current-voltage ( I-V ) characteristic colours available or less barrier potential of the rheostat.. The basic characteristics of diodes one direction are graphical characteristics showing how the current begins to rise rapidly can! As can be corrected by using lenses and other OPTICAL devices band is on your right sorry, blog. Of amplifying ( or making larger ) signals camouflage patterns in natural daylight rise! Hence the LED allows the v-i characteristics of led experiment in one direction CONCLUSION this experiment focuses on the investigation the! Characteristics: Connections are made as per the connection diagram they are called active devices since are! A greater p.d, v-i characteristics of led experiment increase results in a smaller rise in,. Introducing Ohm ’ s law or current between 10 to 50 milliamperes, the...