In direct current dc, the electric charge current only flows in one direction. The app can be used as a virtual laboratory where a physical lab is not available. Line transients from the ac source are a common cause of an overvoltage fault. An ac current is in the form of a curve, or sine wave, while a dc current is in the form of a straight line. After successful completion, the troubleshooter can improve their understanding of dc, ac, three phase circuits, relays, contactors, plc, electronics, and other related technology. Take the basic acdc power supplies discrete semiconductor devices and circuits worksheet. There are two types of electrical current alternating current ac and direct current dc. Reviews of complex algebra, sinusoids, phasors, phasor relations of circuit elements, impedance and admittance, impedance combinations, series. What is it about this kind of circuit that makes it such a necessary part of many electronic systems. Diagnosing of defective printed circuit boards pcb. Introduction welcome to the dc electrical circuits workbook, an open educational resource oer. Use mydaq digital multimeter dmm to test mysnap components if they appear to be damaged or not working properly. Though designs may vary, the task of converting ac power to dc power is vital in the functioning of a great many electronic devices. Dc motor troubleshooting based on the easa technote troubleshooting dc motors always disconnect the power before handling any parts of the electrical equipment lock out and tag out all electrical circuits test for voltage before touching any components.
Acdc power supply circuits are one of the most common circuit con. If you continue browsing the site, you agree to the use of cookies on this website. In particular, if a coil rotates in the presence of a magnetic field, the induced emf varies sinusoidally with time and leads to an alternating current ac, and provides a source of ac power. The technicians main aid in troubleshooting a circuit in a piece of equipment is the schematic diagram. Chapter 28a direct current circuits a powerpoint presentation by paul e. Finding motor hp horse power, kva kilovolt ampere kw input, when motor hp is known kw kilowatts amperes, when kva is known. Ac electrical theory an introduction to phasors, impedance and admittance, with emphasis on radio frequencies. In phase means that both waveforms peak at the same time. Always use a power switch to remove power when building circuits. Simply switching off circuit breakers will not do the job since it will still leave hot wires on the supply side of the panel. Electric charge in alternating current ac, on the other hand, changes direction periodically. To transform incoming line voltage ac provided by the utility company to a usable voltage, and 2.
Problems in electrical engineering asia publications. Circuit theory i thevenins theorem thevenins theorem states that a linear twoterminal circuit can be replaced by an equivalent circuit consisting of a voltage source v th in series with a resistor r th where v th is the open circuit voltage at the terminals and r. Suppose you were instructed to check the continuity of the switch sw1 mounted on the printed circuit. All exercises are designed to be used for both practice and testing. A transformer with tap adjustments in the secondary side provides a method to reduce and adjust the output voltage level and to isolate the dc circuit.
Tippens, professor of physics southern polytechnic state university a powerpoint presentation by. Seriesparallel circuit troubleshooting experiment complex dc circuits voltage divider circuits bridge circuits introduction to kirchhoffs voltage and current laws kirchhoffs voltage and current laws nortons theorem thevenins theorem multimeter loading day 2 tuesday alternating current part 1 ac fundamentals generating ac electricity. Introductory dcac circuits 6th edition cook, nigel p. After completing this chapter you should be able to. Module 6 dc motors this module describes the types of dc motors and includes discussions of speed control, applications, and load characteristics. Learners will see how electricity is used for power and control in industrial, commercial, agricultural, and residential applications. Introduction to three phase ac and three phase ac transformers. Handson basic electricity training troubleshooting acdc. Ac circuits page 2 of resistors in ac circuits a circuit comprised of a current source and resistor will be first analyzed as seen in the schematic below. Dc circuits are simply those in which the current moves in one direction only thus direct current dc. You are given a 10 volt battery to work with in lab. Lock out and tag out all electrical circuits test for voltage before touching any components check for and eliminate the danger of stored energy caused by raised or springloaded equipment the basic testing equipment you will need to troubleshoot dc motors in the field includes.
Because the wiring and the inputs and outputs ios are the most vulnerable elements in a system, be sure to locate and identify these elements in the problem circuit. Troubleshooting basic principles in using a drawing and meter in troubleshooting circuits circuits equipment troubleshooting ac motors and motor starters fundamentals of ac motors types of ac and dc motors used motor terminal identification and connection diagrams identification and construction connecting up a. Chapter 27 questions 1, 3, 5 chapter 27 problems 7, 19, 49 wileyplus assignment. The schematic diagram is a picture of the circuit that uses symbols to represent the various circuit components.
Assessing student difficulties in understanding the behavior of ac. The trainer covers industryrelevant skills, such as installing, operating, and troubleshooting ac and dc electrical circuits in a variety of applications. In some cases spd circuits are built into the electrical devices themselves. Pdf assessing problem solving skills in understanding and. The function of the bridge rectifier is to convert the incoming ac voltage into dc voltage and the filter capacitor usually have the value of 220uf 400volt to.
An ac wiring decal is affixed to the inside of the louvered cover at the generator end. Kcl as well as ohms law are used in solving the circuit. Sometimes, the only way to test a circuit is to see how the system reacts to a manual input. This module describes the basic concepts of direct current dc electrical circuits and discusses the associated terminology. To convert the usable ac voltage to direct current dc to be used. Now, we will find the equivalent circuit for two terminal resistive circuit with sources. We can find the following quantities by using below formulas chart electrical formulas in dc full load current in amperes alternating current ac motors alternating current ac single. Root square mean the rms voltage v rms is the dc voltage that has the same effect as the actual ac voltage. The test leads are connected in parallel across the circuit load. Your ac needs time to reset its internal circuit breaker. Locate your electrical panel and find the circuit breaker that your ac connects to. The circuit shown here is called a bridge rectifier, and its purpose is to convert alternating current from the powersupply unit into direct current. Solving combination circuit problems the basic technique used for solving dc combination circuit problems is the use of equivalent circuits.
Basic acdc power supplies this worksheet and all related. Simply switching off circuit breakers will not do the job since it will still. In those cases, you can not naively apply the simple formula of rc or rl circuits if those resistors are not just in. Fundamentals of alternating current in this chapter, we lead you through a study of the mathematics and physics of alternating current ac circuits. The rectifier input is an ac voltage from the commercial electrical power grid or an enginegenerator. The unexpected behavior exhibited by the circuit is due to improper locating or soldering of components, component damage due to aging, faults, overheat, and so on. An alternating current ac is a current that varies sinusoidally with time. Apr 24, 2010 troubleshooting electric circuits department of defense 1968 pin 27867 shows how to locate and repair shorted, grounded and open circuits. A technician is troubleshooting a power supply circuit that outputs substantially less dc voltage than it should. Amatrols acdc electrical training system t7017a explores the fundamental concepts of ac and dc electrical systems. Ohms law formula for an ac circuit may be stated as r v i eff eff 12. Electric circuits are used in numerous electrical systems to accom plish different tasks. Electrical troubleshooter for acdc circuits, relays.
Single phase emf generation, average and effective. Monitoring electrical power quality describes many power quality problems. Acdc electrical training system basic electrical circuits. In electrical circuits, the principal elements are the current and voltage, as well as the capacitors, inductors and resistors. The art of debugging circuits massachusetts institute of. Dc circuits mcqs with explanatory answers electrical. In all practical problems of electrical calculations, it is assumed that the temperature rise is. The goal of this workbook is to provide a large number of problems and exercises in the area of dc electrical circuits to supplement or replace the exercises found in textbooks. To simplify a complex circuit to a simple circuit containing only one load, equivalent circuits are substituted on paper for the complex circuit they. This document provides an introduction to the subject of ac circuit analysis, with particular.
We have been investigating students knowledge and understanding of basic concepts in electricity and their application to solving electrical circuit problems. Typical problems of direct rc and rl circuits quite often, the problem likes to ask you the asymptotic behavior of the rc or rl circuits with several resistors. Acdc power supply circuits are one of the most common circuit. With this method, voltage forces electrons to flow first in one direction, then in the opposite direction, alternating very quickly. Be certain to unplug ac power cords and shutdown dc. An indepth troubleshooting guide to help you with your ac electric motor issues. Diodes and diode circuits tlt8016 basic analog circuits 20052006 7 3. Basic circuit troubleshooting basic electricity pdf version. Chapter 27 questions 1, 3, 5 chapter 27 problems 7, 19, 49. Write the general equation for a sinusoidal signal based on its amplitude.
Electricity was first discovered and harnessed, mostly, in the dc, or direct current form. Though designs may vary, the task of converting ac power to dc power is vital in the functioning of a great. If you plug something in the wall it runs on ac although some devices internally convert the ac alternating current into dc. This simple rule can be used in solving simple circuits or in simplifying the solution of complicated ones. Be able to locate and repair open circuit faults using a safe, efficient procedure. Steady state solution due to ac sinusoidal waveforms is in chap.
Why, alternating current and direct current, of course. Electrical troubleshooter for ac dc circuits, relays, contactors and plcs photo credit. The sum of the currents entering a junction is equal to the sum of the. Ac and dc circuits often share the same distributor panel. Segment 2 power introduction to the concept of power in the dc and ac realms. Suppose you were instructed to check the continuity of the switch sw1 mounted on the printed circuit board. The average ac power is the product of the dc equivalent voltage and current. A technician is troubleshooting a power supply circuit that outputs substantially less dc voltage. Lessons in electric circuits, volume ii ac by tony r. Electrical troubleshooting 2 when using the multimeter to make voltage measurements it is important to remember that the voltmeter must always be connected in parallel with the load or circuit under test.
This simulation explores an industrial garage door circuit. Volume 2 of 4 module 3 dc circuits this module introduces the rules associated with the reactive components of inductance and capacitance and how they affect dc circuits. Use eye protection when experimenting on your own circuits. While dc motors require the use of brushes to make electrical contact with moving coils of wire, ac motors do not. Alternating current ac versus direct current dc the contrast between ac and dc isnt just rooted in physics but goes as far back as the 1800s when, for a period of time, both vied for the residential, commercial and industrial markets. So in the process of air conditioner troubleshooting, you need to know the basics of air conditioners. Solving a simple circuit of three elementsa simple circuit is solved and power absorbed or supplied by each element is determined.
A common example of this type of circuit would be an incandescent light bulb where the resistive element is the filament of the bulb. Leave your thermostat off for at least half an hour. This type of voltage is called alternating current ac voltage. Air conditioner troubleshooting good ac repair tips 1 how to. It is offered free of charge under a creative commons. Acdc power supply circuits are one of the most common circuit configurations in electronic systems. Although we use circuits to accomplish almost magical feats long distance wireless. The problems involved with making and breaking electrical contact with a moving coil should be. Be sure that all connections are securely fastened. Circuit troubleshooting is the highest level of thinking required of many electrical and electronics professionals. Read chapters 26, 27 chapter 26 questions 1, 3, 10 chapter 26 problems 1, 17, 35, 77.
While dc motors require the use of brushes to make. The generators data plate gives the voltage, current and frequency rating of the generator. Electrical troubleshooter for acdc circuits, relays, contactors and. Sinusoidal signals are perhaps the most important signal forms since once the circuit response to sinusoidal signals are known, the result can be generalized to predict how the circuit will respond to a much greater variety of signals. Troubleshooting of an electronic circuit is a process of having a special outlook on components that comes out with remedies to repair it. Module 4 section 4 rectifier inspecttroubleshoot final 10.
Be sure that parts with positive or negative markings are positioned as shown in the drawings. In fact, ac and dc motor designs are very similar to their. Its easy to blame an ac electrical problem on lightning or power outages, but it could just as easily be out due to contact with water. Fundamentals of direct current circuits ced engineering. Welcome to the dc electrical circuits workbook, an open educational resource oer. You also need to understand basic techniques for troubleshooting different electrical and mechanical aspects of the system as a whole. Troubleshooting motor circuits tmc is simutech multimedias third troubleshooting simulation. A technician is troubleshooting a power supply circuit with no dc output voltage. Jul 26, 2016 ac electrical problems after a storm or power outage. Circuit breaker serves as an on off switch and overload protection. Lessons in electric circuits, volume ii ac ibiblio. Volume 3 of 4 module 7 basic ac theory this module describes the basic concepts of alternating current ac electrical circuits and discusses the associated terminology. Dc circuits outline 1 basic concepts 2 basic laws 3 methods of analysis 4 circuit theorems.
The rectifier is used to deliver or impress a direct current onto a structure. Ac dc power supply circuits are one of the most common circuit configurations in electronic systems. Most circuit problems are due to incorrect assembly, always double check that your circuit exactly matches the drawing for it. The generator is a singlephase, reconnectable 120 volt ac twowire or 115 volt ac twowire or 230 volt ac twowire, at 50 hertz. The manual contains sufficient exercises for a typical 15 week course using a two to three hour practicum period. This basic electrical training system includes voltage regulators, resistors, capacitors, inductors, toggle switches, indicator lamps, and much more.
This manual is intended for use in a dc electrical circuits course and is appropriate for two and four year electrical engineering technology curriculums. Both ac and dc describe types of current flow in a circuit. Before getting into details of printed circuit board, there are some basics you need to know about circuits. Basic circuit troubleshooting worksheet basic electricity. Analogue signature analysis to test the unpowered printed circuit boards pcbs. If youre struck with thunderstorms and heavy downpours, you may want to check for minor flooding that may be affecting your air conditioner. Ac dc power supply circuits are one of the most common circuit con. Your professionals will learn to diagnose and repair multiple faults, honing their skill at troubleshooting motor circuits. In this post, the voltage divider circuit is studied and some examples are solved to show how this rule can be deployed in solving circuits. Introduction to single phase ac, differences between ac and dc, ac applications, complex math based representation of ac circuits and associated circuit analysis. Transients in rl, rc and rlc circuits with dc excitation. In particular, if a coil rotates in the presence of a magnetic field, the induced emf varies sinusoidally with time and leads to an alternating current ac, and provides a source of ac.
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