50 Simple L.E.D. Circuits
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Transistor Circuit Guidebook Byron Wels TAB BOOKSBLUE RIDGE SUMMIT, PA
TAB BOOKS No. 470 34.95 By Byron Wels TransistorCircuit GuidebookByronWels TABBLUE RIDGE BOOKS SUMMIT,PA. 17214 Preface beforemeIa supposepioneer (along the my withintransistor firstthe many field.experiencewith wasother Weknown. World were using WarUnlike solid-stateIIsolid-state GIs) today's asdevices somewhat experimen- receivers marks of FIRST EDITION devicester,ownFirst, withsemiconductors! youwith a choice swipedwhichor tank. ofto a sealed,Here'sexperiment, pairThen ofhow encapsulated, you earphones we carefullywe did had it: from totookand construct the veryonenearest exoticof our the THIRDSECONDFIRST PRINTING-SEPTEMBER PRINTING-AUGUST PRINTING-JANUARY 1972 1970 1968 plane,wasyouAnphonesantenna. emptywound strung jeep,apart After toiletfull outand ofclippingas paper wire,unwoundhigh closelyrollandthe servedascatchthe far spaced.wire offas as itfrom a thewouldsafetyThe thecoil remaining-pin,magnetreach-for form, you inside.which stuckwire the Copyright © 1968by TAB BOOKS coatedNext,it into youneeded,a hunkribbons of -ofwooda razor -steel, soblade.the but point Oh,aItblued was noneprojected placedblade of the -quenchat so fancy right the pointplastic-bluedangles.of -, Reproduction or publicationPrinted inof the ofAmerica the United content States in any manner, with- themindfoundphoneground pin you,the was couldserved right not wired contact lacquerspotas toa onground blade, it. theblued.blade'sAconnector, pin,bayonet bluing,and stuck antennaand you hilt thecould coil.-deep other actuallyIfin ear- youthe isoutherein. assumed express -
Unit-1 Mphycc-7 Ujt
UNIT-1 MPHYCC-7 UJT The Unijunction Transistor or UJT for short, is another solid state three terminal device that can be used in gate pulse, timing circuits and trigger generator applications to switch and control either thyristors and triac’s for AC power control type applications. Like diodes, unijunction transistors are constructed from separate P-type and N-type semiconductor materials forming a single (hence its name Uni-Junction) PN-junction within the main conducting N-type channel of the device. Although the Unijunction Transistor has the name of a transistor, its switching characteristics are very different from those of a conventional bipolar or field effect transistor as it can not be used to amplify a signal but instead is used as a ON-OFF switching transistor. UJT’s have unidirectional conductivity and negative impedance characteristics acting more like a variable voltage divider during breakdown. Like N-channel FET’s, the UJT consists of a single solid piece of N-type semiconductor material forming the main current carrying channel with its two outer connections marked as Base 2 ( B2 ) and Base 1 ( B1 ). The third connection, confusingly marked as the Emitter ( E ) is located along the channel. The emitter terminal is represented by an arrow pointing from the P-type emitter to the N-type base. The Emitter rectifying p-n junction of the unijunction transistor is formed by fusing the P-type material into the N-type silicon channel. However, P-channel UJT’s with an N- type Emitter terminal are also available but these are little used. -
Phys 586 Laboratory Lab11
Phys 586 Laboratory Lab11 Goal: In this lab you will make measurements with a photodiode. While not the same type of diode used in diode arrays for radiation planning or microstrip detectors in high energy physics, many of the basic device characteristics are the same. Additionally, photodiodes are used in x-ray imaging (along with a scintillator layer) and avalanche photodiodes find application in high energy physics. Reading: See Photodiode Characteristics article in the Readings. Lab: 1. Construct the LED circuit shown in Figure 1. a) Is the LED forward or reverse biased? The LED is forward biased. b) What is the purpose of the resistor? The value of the resistor is chosen so that the specified LED operating current results in the desired LED voltage drop. The value that this resistor should have can be determined using Kirchhoff’s loop rule and Ohm’s Law. Vary the voltage and convince yourself the brightness of the LED changes. Note the longer leg on the LED is the anode. 1 2. Measure the current through the LED and the voltage across the LED for LED supply voltages of 2.5, 5, 8, 10, 13, 15, 18 and 20V. LED LED LED Supply Voltage Current Voltage (V) (V) (mA) 2.5 1.67 2.46 5.01 1.76 4.91 8.01 1.82 7.8 10.05 1.85 9.9 13 1.9 12.83 15 1.92 14.9 18 1.96 17.82 20 1.99 20.1 Circuit 1: LED Current vs LED Voltage 25 20 15 10 LED Current (mA) 5 0 1.65 1.7 1.75 1.8 1.85 1.9 1.95 2 2.05 LED Voltage (V) 2 3. -
Photodiode and LIGHT EMITTING DIODE
Photodiode and LIGHT EMITTING DIODE Presentation by JASWANT KUMAR ROLL NO.-12 rd IT(3 SEM.) 1 About LEDs (1/2) • A light emitting diode (LED) is essentially a PN junction opto- semiconductor that emits a monochromatic (single color) light when operated in a forward biased direction. • LEDs convert electrical energy into light energy. LED SYMBOL 2 ABOUT LEDS (2/2) • The most important part of a light emitting diode (LED) is the semi-conductor chip located in the center of the bulb as shown at the right. • The chip has two regions separated by a junction. • The junction acts as a barrier to the flow of electrons between the p and the n regions. 3 LED CIRCUIT • In electronics, the basic LED circuit is an electric power circuit used to power a light-emitting diode or LED. The simplest such circuit consists of a voltage source and two components connect in series: a current-limiting resistor (sometimes called the ballast resistor), and an LED. Optionally, a switch may be introduced to open and close the circuit. The switch may be replaced with another component or circuit to form a continuity tester. 4 HOW DOES A LED WORK? • Each time an electron recombines with a positive charge, electric potential energy is converted into electromagnetic energy. • For each recombination of a negative and a positive charge, a quantum of electromagnetic energy is emitted in the form of a photon of light with a frequency characteristic of the semi- conductor material. 5 Mechanism behind photon emission in LEDs? MechanismMechanism isis “injection“injection Electroluminescence”.Electroluminescence”. -
LED Circuit and Device Physics 120 Pts Objective: Meas
Applied Quantum Mechanics for Electrical Engineers Workshop III – LED Circuit and Device Physics 120 pts Objective: Measure the voltage drop across an LED in a simple circuit, demonstrate that the voltage drop is proportional to the band gap of the semiconductor material, and analyze the behavior of the circuit in terms of the device physics of the PN junction. Background: A light emitting diode (LED) is a device that is designed by fabricating a PN junction or diode as illustrated in Figure 1. Figure 1. Schematic of LED and illustration of carrier movement resulting in emission of light. Image: http://blog.ucsusa.org/wp-content/uploads/2014/10/UCS-LED-how-it-works-graphic.gif A simple PN junction can be fabricated by growing a p-type material on top of an n-type material, or by doping an n-type material with sufficient p-type dopants so that the surface becomes p-type. The energy band diagram for a PN Junction under forward bias conditions is illustrated in Figure 2, along with a schematic of the circuit under forward bias. Figure 2. LED circuit and PN Junction energy band diagram illustrating carrier movement under forward bias. Image: http://www.vit.ac.in/onlinelab/m9.aspx The application of a forward bias to the circuit results in a decrease in the barrier to electron movement from the n-side to the p-side. Likewise, the barrier of hole movement from the p- side to the n-side is also reduced. Thus, majority carriers from each side are able to cross the energy barrier. -
Stroboscopic: Andy Warhol and the Exploding Plastic Inevitable Homay King Bryn Mawr College, [email protected]
Bryn Mawr College Scholarship, Research, and Creative Work at Bryn Mawr College History of Art Faculty Research and Scholarship History of Art 2014 Stroboscopic: Andy Warhol and the Exploding Plastic Inevitable Homay King Bryn Mawr College, [email protected] Let us know how access to this document benefits ouy . Follow this and additional works at: http://repository.brynmawr.edu/hart_pubs Part of the History of Art, Architecture, and Archaeology Commons Custom Citation H. King, "Stroboscopic: Andy Warhol and the Exploding Plastic Inevitable," Criticism 56.3 (Fall 2014): 457-479. This paper is posted at Scholarship, Research, and Creative Work at Bryn Mawr College. http://repository.brynmawr.edu/hart_pubs/72 For more information, please contact [email protected]. King 6/15/15 Page 1 of 30 Stroboscopic:+Andy+Warhol+and+the+Exploding+Plastic+Inevitable+ by+Homay+King,+Associate+Professor,+Department+of+History+of+Art,+Bryn+Mawr+College+ Published+in+Criticism+56.3+(Fall+2014)+ <insert+fig+1+near+here>+ + Pops+and+Flashes+ At+least+half+a+dozen+distinct+sources+of+illumination+are+discernible+in+Warhol’s+The+ Velvet+Underground+in+Boston+(1967),+a+film+that+documents+a+relatively+late+incarnation+of+ Andy+Warhol’s+Exploding+Plastic+Inevitable,+a+multimedia+extravaganza+and+landmark+of+ the+expanded+cinema+movement+featuring+live+music+by+the+Velvet+Underground+and+an+ elaborate+projected+light+show.+Shot+at+a+performance+at+the+Boston+Tea+Party+in+May+of+ 1967,+with+synch+sound,+the+33\minute+color+film+combines+long+shots+of+the+Velvet+ -
Thyristors.Pdf
THYRISTORS Electronic Devices, 9th edition © 2012 Pearson Education. Upper Saddle River, NJ, 07458. Thomas L. Floyd All rights reserved. Thyristors Thyristors are a class of semiconductor devices characterized by 4-layers of alternating p and n material. Four-layer devices act as either open or closed switches; for this reason, they are most frequently used in control applications. Some thyristors and their symbols are (a) 4-layer diode (b) SCR (c) Diac (d) Triac (e) SCS Electronic Devices, 9th edition © 2012 Pearson Education. Upper Saddle River, NJ, 07458. Thomas L. Floyd All rights reserved. The Four-Layer Diode The 4-layer diode (or Shockley diode) is a type of thyristor that acts something like an ordinary diode but conducts in the forward direction only after a certain anode to cathode voltage called the forward-breakover voltage is reached. The basic construction of a 4-layer diode and its schematic symbol are shown The 4-layer diode has two leads, labeled the anode (A) and the Anode (A) A cathode (K). p 1 n The symbol reminds you that it acts 2 p like a diode. It does not conduct 3 when it is reverse-biased. n Cathode (K) K Electronic Devices, 9th edition © 2012 Pearson Education. Upper Saddle River, NJ, 07458. Thomas L. Floyd All rights reserved. The Four-Layer Diode The concept of 4-layer devices is usually shown as an equivalent circuit of a pnp and an npn transistor. Ideally, these devices would not conduct, but when forward biased, if there is sufficient leakage current in the upper pnp device, it can act as base current to the lower npn device causing it to conduct and bringing both transistors into saturation. -
LUXEON Illumination Leds Circuit Design and Layout Practices to Minimize Electrical Stress
ILLUMINATION LUXEON Illumination LEDs Circuit Design and Layout Practices to Minimize Electrical Stress Introduction LED circuits operating in the real world can be subjected to various abnormal electrical overstress situations. Among the most common are: • Isolation test during validation or production of the luminaire (“hi-pot test”) • Lightning strikes and line transients • Hot-swapping of LED circuits (disconnecting and reconnecting an LED circuit board to the driver while the driver remains powered up) • Driver failures • ESD (Electro-Static Discharge) Scope This paper presents background information on some of these overstress modes and discusses recommendations to minimize the potentially destructive effects of electrical overstress on LEDs. AB06 LUXEON LEDs Application Brief ©2016 Lumileds Holding B.V. All rights reserved. Table of Contents Scope . 1 1 . Electrical Overstress . 3 2 . Isolation Test Requirements . 3 3 . Isolation Test on an LED Board . 4 4 . LUXEON Rebel LED Circuit Model on a Board . 5 5 . Electrical Stress Simulation during Isolation Test . 6 6 . Protection Circuits . 8 7 . High Voltage Drivers . 10 8 . Lightning Strikes and Line Transients . 11 9 . Recommendations . 11 About Lumileds . 12 AB06 LUXEON LEDs Application Brief 20170605 ©2017 Lumileds Holding B.V. All rights reserved. 2 1. Electrical Overstress Electrical Overstress (EOS) can present itself to an LED array in two forms, either as excess voltage or excess current. Because voltage and current are interrelated, it is not always possible to identify whether a high voltage or high current caused a failure. Currents can flow through an LED array in two ways: differential mode and common mode (see Figure 1). Differential mode currents can be very destructive. -
The Importance of Leds in Switches
WHITEPAPER The Importance of LEDs in Switches LEDS PROVIDE ADDITIONAL OPTIONS FOR DESIGNERS AND IMPROVE THE FUNCTIONALITY OF THE SWITCH NKK SWITCHES THE IMPORTANCE OF LEDs IN SWITCHES Why put an LED on a switch? LEDs are a simple, compact way to indicate the status of a circuit. By having the LED in the switch, it reduces space and component count for an assembly. There are many ways to control LEDs. Some indicator circuits use the switch’s own circuity in an ON-OFF fashion. Others are bicolor or even RGB and are hooked up to a microprocessor to give additional visual feedback. Most of the illuminated switches available at NKK Switches have the LED circuit separate from that of the switching circuit. This is to provide maximum flexibility for design. 1. The two circuits found in an illuminated switch (single pole) Switching Circuit LED Circuit UB2 1 L (+) L(+) NC NC R1 +VDC Switching NO NO LED Circuit Circuit 3 2 GND L(-) L (-) COM COM The simple indicator circuit shown above is one that uses a spare pole on the switch to turn OFF and ON the LED to show that a circuit is connected. This type of circuit just shows the state of the switch, either OFF or ON, with the reasonable assumption that if the LED is illuminated then the load circuit is active as well. 2. Simple single LED ON-OFF indicator using the second pole of a double pole switch to light the LED. The dotted line indicates that the two poles are mechanically connected to each other. -
Circuit Topology Analysis for LED Lighting and Its Formulation Development
energies Article Circuit Topology Analysis for LED Lighting and its Formulation Development William Chen, Ka Wai Eric Cheng * and Jianwei Shao Power Electronics Research Centre, Department of Electrical Engineering, The Hong Kong Polytechnic University, Kowloon 999077, Hong Kong, China; [email protected] (W.C.); [email protected] (J.S.) * Correspondence: [email protected] Received: 30 July 2019; Accepted: 24 October 2019; Published: 4 November 2019 Abstract: Light emitted diode (LED) is becoming more popular in the illumination field, and the design of LED lighting is generally made to provide illumination at lower power usage, helping save energy. A power electronic converter is needed to provide the power conversion for these LEDs to meet high efficiency, reduce components, and have low voltage ripple magnitude. The power supply for LED is revisited in this paper. The LEDs connected in series with diode, transistor, or inductor paths are examined. The formulation for each of the cases is described, including the classical converters of buck, boost, buck–boost, and Cuk.´ The circuit reductions of the classic circuit, circuit without the capacitor, and without a freewheeling diode are studied. Using LED to replace freewheeling diodes is proposed for circuit component reduction. General equations for different connection paths have been developed. The efficiency and output ripple amplitude of the proposed power converters are investigated. Analytical study shows that the efficiency of proposed circuits can be high and voltage ripple magnitude of proposed circuits can be low. The results show that the proposed circuit topologies can be easily adapted to design LED lighting, which can meet the criteria of high efficiency, minimum components, and low-voltage ripple magnitude at the same time. -
621 212 Electronics and Communication Engineering Ec6304/Linear Integrated Circuits
DSEC/ECE/EC6304-LIC/QB 1 DHANALAKSHMI SRINIVASAN ENGINEERING COLLEGE -621 212 ELECTRONICS AND COMMUNICATION ENGINEERING EC6304/LINEAR INTEGRATED CIRCUITS QUESTION BANK UNIT 1(2 MARKS) 1. What is an integrated circuit? APRIL/MAY 2010 An integrated circuit (IC) is a miniature, low cost electronic circuit consisting of active and Passive components fabricated together on a single crystal of silicon. The active components are Transistors and diodes and passive components are resistors and capacitors. 2. What is current mirror? APRIL/MAY 2010 A constant current source (current mirror) makes use of the fact that for a transistor in the active mode of operation, the collector current is relatively independent of the collector voltage 3. What are two requirements to be met for a good current source? MAY/JUNE 2012 a. Superior insensitivity of circuit performance to power supply variations and temperature. b. More economical than resistors in terms of die area required providing bias currents of small value. c. When used as load element, the high incremental resistance of current source results in high voltage gains at low supply voltages. 4. What are all the important characteristics of ideal op-amp? APRIL/MAY 2015 Ideal characteristics of OPAMP 1. Open loop gain infinite 2. Input impedance infinite 3. Output impedance low 4. Bandwidth infinite 5. Zero offset, ie, Vo=0 when V1=V2=0 5. Define CMRR of OP-AMP APRIL/MAY 2011 The relative sensitivity of an op-amp to a difference signal as compared to a common - mode signal is called the common -mode rejection ratio. It is expressed in decibels. -
Precision Stroboscope
Computer Aided Engineering & Measurement Systems Precision Stroboscope Features & Capabilities • Precision Constant Duty Cycle Stroboscope • Wide operating flash rate 0Hz - 10kHz • Fine Frequency Resolution of 0.01Hz • SuperFlux High Power White LED technology • Collimating Lens with 45° Beam Width • Long Flash LED Lifetime 50K - 100K Hours • Wide Range Sync Capability 0.5V - 300V • Fully Programmable via RS-232 • Four (4) Operating Modes • Four (4) Parameter Display Modes • 6 Digit 7-Segment Numeric Display • Backlit Status Indicators • Win32 Application Software • High Capacity Lithium Ion Battery • Portable Hand Held Battery Operated • Small & Lightweight Flashlight Size Chassis • Built-in Universal Charger 85VAC-265VAC LS310 - Precision High Speed Stroboscope The LS310 is a portable battery operated hand-held instrument roughly the same size as a flashlight. Shaped as an octagon, it is 2 inches across and 7 inches long weighing less than one pound. The LS310 utilizes a rechargeable Lithium Ion battery and features a universal 85-265VAC built-in charger. The LS310 utilizes the latest in high power LED technology with a 7 Watt SuperFlux high efficiency multi LED and collimating lens. The intensity is very bright with each flash producing nearly 200 lumens of white light. A strobe based on LED technology has several important advantages over traditional Xeon based strobes: (1) Flash duration can be programmed and controlled precisely over an extremely large range from seconds down to sub-micro seconds, (2) the life of the LED is virtually unlimited, (3) programmable flash intensity, and (4) lower cost low voltage drive circuitry. The highly controllable LED flash duration enables constant duty cycle operation vs.