# basic electrical theory

Basic Electrical Theory: Electric Circuit. An electric circuit provides a path for the current to flow to a from a point. 2. Now let’s take the same toy and rewire it so that the speaker and LEDs are in parallel with the power source, as seen below. In other words, it is a measurement of the work required to move a unit charge between two points. This law states that the algebraic sum of the voltages in a closed loop is always equal to zero. Written work from the Ancient Egyptians dating back to 2750 BC mentioned a type of fish they called âThunderer of the Nileâ. How much opposition the conductor or metal wire presents to the electric current flow is the electrical resistance. Ancient writings from Pliny the Elder and other naturalists described a numbing effect when shocked by a catfish or a torpedo ray, and realized such a shock could travel along a conductive object. Electrical resistance, measured in Ohms, is the measure of the amount of current repulsion in a circuit. Electrician Training in Montana | Earn Big By Becoming an ElectricianÂ, Basic Electrical Theory: Understanding Electricity, Electrician Career Advice: A Fun and Challenging Trade. You have probably experienced the pain involved with installing Christmas lights only to realize none of them work. Because of this, most electrical circuits are wired in parallel. When resistors are connected this way, their resistances add together and increase the total circuit resistance. It is the continuous and uniform flow (called a drift) of electrons (the negative particles of an atom) around a circuit that are being “pushed” by the voltage source. electricity can kill you! The total current supplied from the power source is divided among each of the branches but voltage is common throughout. In its simplest terms, electricity is the movement of charge, which is considered by convention to be, from positive to negative. Fortunately, a lot of the new light strands are wired in parallel. Voltage is the force that pushes the current through electrical circuits. Using Ohm’s law, we can reconfigure the formula to solve for current in the loop, or I (loop) = V (loop)/ R (loop). This Electrical Career Now free practice test covers electrical theory, electrician trade knowledge, wiring, installation, safety, load calculations, and more. Doing the same for the other loop, we get I(R2) = V(R2)/R2 , I(R2) = 5VDC/284Ω = 17.6mA. R1 is equal to 430 Ohms, R2 is equal to 284 Ohms and the supply is a battery with 5VDC and 5A. What is electricity? Insulators, like plastic or wood, have electrons which are much more tightly bound to the nucleus, which means that they are harder to move around. ELECTRICAL THEORY AND APPLICATION volts.pdf 3/15/04 Rev:1.2 Page 2 2004 L&L Kiln Mfg, Inc. P.O.B 1898, Boothwyn, PA 19061 P:610.485.1789 F:610.485.4665 E:sales@hotkilns.com ww.hotkilns.com ELECTRICAL BASICS ELECTRICAL SAFETY Electricity is a wonderful utility, but can be dangerous if not approached carefully. The amount of current is based on the supply voltage and the resistance in the circuit. Cue Clark Griswold! The current in series circuits is constant throughout but the voltage may vary. All of the current in the circuit has to travel through each part of a series circuit. Electrician  Safety - Because Your Health Is Vital, An Overview of Electrician Tools You'll Need In The Field, About Me  |  Privacy Policy  |  Site Map  |  What's New  |  Contact Me. From talkies to eight tracks to screaming “I want my MTV”, even hashtagging, none of it would be possible #WithoutElectricity. Learn the basics of the electrical trade, including electrical safety, circuits, and electrical theory, with the free online Electrical courses from Alison. Let’s start with three very basic concepts of electricity: namely, electric charge, electric current, and electric circuit. The electric current always flows from positive to negative, and takes the path with the least resistance. Electricity is defined as “the flow of electrons through simple materials and devices” or “that force which moves electrons.” Scientists think electricity is produced by very tiny particles called electrons and protons. Therefore if one light goes out, then only that branch of the circuit will be out. Learn vocabulary, terms, and more with flashcards, games, and other study tools. If you have two channels in a river and one is partially blocked by logs, then most of the water will flow through the clear channel. You will find them in all electrical systems. However, electricity remained mostly a strange phenomenon until 1600, when the English scientist William Gilbert began to study electricity more closely. Thomas Edison and Alessandro Volta were pioneers in DC current and wrote much of electricity’s history. Suffice it to say that two of the tiny particles that make up atoms — protons and electrons — are the bearers of electric charge. When electrons flow against the opposition offered by resistance in the circuit, friction occurs and heat is produced. One of the big industries spawned from electrical principles is automation. The three primary forces in electricity are voltage, current flow and impedance (resistance). The negative charge is carried by electrons, while the positive charge is carried by the protons, and neutrons are naturally neutral. Also, as a material heats up, its resistance increases, and the resistance decreases as it cools down. No current will flow to the other lights because of the open circuit path. safetyis the most important thing. Fusing that branch would save little Suzie’s favorite toy and fusing is a very important part of design both in circuits and in systems as a whole. Current is measure in units of Amperes, or Amps for short, and is equal to one Coulomb (the amount of charge that 6.242Ã10. We provide different types of electrician job descriptions, and help you to understand what to expect. Learn the basics of what electricity is, and how it works. Volume 1 of 4 Module 1 - Basic Electrical Theory This module describes basic electrical concepts and introduces electrical terminology. No, we’re not going to add the two branch currents together (smart, but too easy); we’ll use Ohm’s law and the parallel resistance calculation. Looking at the node (connection between two loops) in the diagram below, we already know that to be true: 0 = 29.23mA – (11.63mA + 17.6mA). Since all of the lights are in-line with each other, if one goes out it causes an open circuit at that point. The name â electromotive force â implies this is a force, when in fact the e.m.f. An example of this is often seen when someone is working without wearing properly insulated footwear. Long before anyone heard the word electricity, people had seen lightning and experienced shocks from electric fish. No matter how the charge is created, chemically (like in batteries) or physically (friction from socks and carpet), the movement of the discharge is electricity. The proton carries a single unit positive charge equal in magnitude to the electron charge. No single discovery has affected our lives, our culture and our survival more than electricity. Parallel wiring simply means that there are multiple paths for the current to travel. When a conductive path is provided for excess electric charge to take, the electric charge moves and creates an electric current. This equation can be combined with Ohm’s law to solve for values that are unknown. So now that we know the current in the loop is 7mA and in a series circuit that current is constant throughout, we can use Ohm’s law to calculate the voltage supplied to the speaker: V(speaker) = I(loop) x R(speaker) or V(speaker) = (7mA) x (430Ω) or ~ 3VDC. Read on to discover more about basic electrical theory. Try this amazing Engineering Quiz: A Basic Electrical Theory Assessment Test quiz which has been attempted 3453 times by avid quiz takers. In its simplest terms, electricity is the movement of charge, which is considered by convention to be, from positive to negative. This law basically states that current into a node will equal the current out of the node. •voltage always follows the path of least resistance •it takes less than 1 amp of current to stop your heart. In it, he explained measurements of applied voltage and current by using a simple electrical circuit made with varying lengths of wire. False. I hope this information helps to refresh that which may have been forgotten. Set up the formula for current or I(R1) = V(R1)/R1 which is solved to be, I(R1) = 5VDC/430Ω = 11.63mA. As you add more devices in parallel, the total circuit resistance goes down and the current increases. Inside there are two junctions of semiconductors. Therefore today, most portable devices use DC power while power plants produce AC. BASIC ELECTRICAL THEORY 1 next> ATOM AND ITS FORCES. Time for a little recap: in series circuits, current is constant and voltage varies but in parallel circuits voltage is constant and current varies. Let’s also find the total current draw by the whole circuit. Here we go, 1/R(total) = 1/R1 + 1/R2 = 1/430Ω + 1/284Ω = 0.0058467… Now reciprocate back to get R(total) = 171Ω. Using the supplied values, we can calculate that I (loop current) = 5VDC/714Ω = 7mA. An example of this is often seen when someone is working without wearing properly insulated footwear. As mentioned previously, with parallel circuits the voltage across each branch will be equal to the supply voltage. Start studying Basic Electrical Theory. In series circuits we would just add all of the resistance values together. DC is current that flows in one direction with a constant voltage polarity while AC is current that changes direction periodically along with its voltage polarity. This leaves us with the letter R which represents Resistance. Electrical theory is a basic building block that every potential electrician must understand from the start. The charge of one electron will counteract the charge of one proton, and atoms tend to prefer to stay at a balanced charge. As mentioned previously, current is the measurement of the flow of charge in a circuit. For an example, imagine where the medical field would be without electricity and in that sense how many lives have been saved due to electrical devices like defibrillators, pacemakers, etc. Loads connected in series form a continuous loop and provide only one path for the current to travel. The current will prefer to take the path with the lowest resistance. But as societies grew the use of DC over long transmission distances became too inefficient. The following concepts are foundational to electrical theory: Electrons: Electrons are subatomic particles that have a negative charge. To jump right in to the theory, check out these articles from the basic electrical theory section, covering core topics like voltage, current, and resistance. An example of this is often seen when someone is … Using Ohm’s law, I can also calculate the current in each loop or branch. The open will be isolated to that branch and current will continue to the other lights in the strand, Joy…to… the…World! 1. When an atom has too many electrons, it will want to release those electrons to something with a weaker charge. Also, from Ohm’s we know that E = IR, so combine this with P = IE and we get P = I^2R. To apply these concepts, have a look at the basic electrical circuits articles to learn about series, parallel, and other types of circuits and their applications. This circuit is known as a voltage divider circuit. Current is measure in units of Amperes, or Amps for short, and is equal to one Coulomb (the amount of charge that 6.242Ã1018 electrons have) per second. There is probably one bulb out somewhere in the hundreds that you hung up. GO … Electric charge refers to a fundamental property of matter that even physicists don’t totally understand. In our example both channels are partially blocked but the one that is most clear (R2) will receive the most current. Resistance is also affected by the material itself. Resistors are self-contained packages of resistance that can be added to a circuit and are commonly used to divide voltage levels. V (voltage) = I (current) x R (resistance). The lower the resistance, the easier current will flow. With one of our electrical studies courses, you can easily gain a better understanding of electrical wiring systems, electrical drawings, and test equipment. The following is a brief description of the information presented in each module of the handbook. The supply voltage was divided among the loads in proportion to the resistance each load carries. AC motors are electric motors driven by alternating current (AC). Using the previous parallel example, we can find the power consumed by the circuit. Comprehensive guide to electrician training in Montana, types of licenses, job market, wages and career opportunities available for aspiring electricians. We can determine the circuit resistance with the formula: 1/R(total) = 1/R(first device) + 1/R(second device) + 1/R(third device) â¦. An electric circuit provides a path for the current to flow to a from a point. This voltage drop principle leads to another important law in basic electrical engineering, Kirchoff’s Voltage Law (KVL). KVL really comes in handy when there are multiple supplies in a loop or multiple loops. Using this value we can now find I(total) = V(total)/R(total) = 5VDC/171Ω = 29.23mA. Basic electrical quantities: current, voltage, power. The supply offers 5 amps of current but the circuit will only use what is demanded by the loads. [hozbreak]. The most fundamental law in electricity is Ohm’s law or V=IR. The current will prefer to take the path with the lowest resistance. So what is electricity and where does it come from? If the worker comes in contact with something that is electrically charged, like an exposed wire or the terminal on a battery, they will experience an electrical shock because the body offers a, When a conductive path is provided for excess electric charge to take, the electric charge moves and creates an electric current. Nikola Tesla changed all that with the invention of alternating current electrical systems. Electrical Theory Practice Test Results Take our online electrical theory practice test and see the type of questions on an electrician licensing exam. Remember these facts: 1) Voltage is the pressure or the Electromotive Force that will push or pull electrons 2) Amperage is the number of electrons moving through a wire or conductor Using these two values, the power consumed by the toy would be: P(total) = (5VDC)^2/171Ω = 146mW. In other words, the net current in a node is zero or 0 = I(in) – I(out). R1 had a higher resistance and received 3VDC of the total 5VDC supply and R2 received the rest or 2VDC. Electricity makes no sound, doesn’t have an odour, and can’t be seen, so understanding the power you’re dealing with in theory, helps to make you and others safe. Simply, resistance resists current flow. How much opposition the conductor or metal wire presents to the electric current flow is the electrical resistance. Resistors in series. Resistance in a circuit can also be helpful when needing to alter voltage levels, current paths, etc. If we only knew the supply potential and the voltage drop of R1, we could use KVL to find the other voltage drop. For additional information on electrical engineering, please go to any of the following sources: IEEE, ISA, and Electrical Codes. Electrical resistance is measured in units of Ohms. These are the electrical quantities used to describe basic electrical theory. The Electrical Science handbook consists of fifteen modules that are contained in four volumes. Basic Electrical Theory 0.0 0 Reviews SKU: RVI-11479 Duration: 20 Minutes This course on basic electrical theory will equip you with the knowledge you need to handle various calculations involving electrical circuits, both AC (alternating current) and DC (direct current). In parallel, you have to add the reciprocals of all the resistance values together and then reciprocate back. Resistance is also affected by the material itself. Some systems may be more complicated and complex, while others might be very simple, but every one will contain these quantities. A larger wire size has less resistance and will allow more current to flow. (electromotive force) is voltage generated by a source of energy, or by varying the magnetic field, as discovered by Faraday. Analyzing a resistor circuit with two batteries. Even though basic electrical theory was not understood until much later, electricity has existed in the world since the beginning of time. The number of protons in an atom does not change because they are locked in the nucleus. Well, in a short there is no resistance, so all of the current would flow though that branch. We will use the positive to negative (clockwise) path. This circuit consists of a battery as the source of electrical energy, a lamp as the electrical load, and two wires … Most metals are good conductors, which means they have low resistance, because their electrons can be gained and lost very easily. Parallel circuits are those which branch off from the power supply. More than likely it is because one of the lights decided to break or burn out and because they are wired in series the rest are now out as well. Ohmâs Law is the fundamental equation for electricity and governs the vast majority of electrical work that we do. We explain concepts like electricity, resistance, voltage, inductors, capacitors, electromagnetism, and more. They are the fundamental forces that control every electrical circuit everywhere. To help further understand the ins and outs of electricity and electrical principles, search the plethora of electrical engineering books available online. All Rights Reserved. is the energy or potential per unit of charge. The next component of Ohm’s law is current, the units of which are Amperes; in the formula, current is represented by the very logical choice of the letter I. It states that an invisible fluid known as electricity tended to flow through a wire from the positive to the negative. The rate of flow of charge in respect of time is known as electric current. R1 represents the resistance value of the speaker and R2 shows the resistance value of the LEDs. The electrons attraction to the nucleus is called _____. Also explore over 83 similar quizzes in this category. Ben’s theory became the convention (hence the term “conventional current”) in electrical theory, mathematics, textbooks and electrical The most common application for resistance in a circuit is the light bulb. The wire could overheat causing the worm to lose its glow and quite possibly everything else. What is the voltage supplied to the LEDs and to the speaker? Automation is electricity working for you to accomplish a task. There are three basic The current through a conductor between two points is directly proportional to the voltage across the two points.I = V / R or V = IR or R = V/IWhere I is the current through the conductor in units of amperes, V is the voltage measured across the conductor in units of volts, and R is the resistance of the conductor in units of ohms. First, we need to find the current in the loop once the belly is pressed and switch 1 (S1) closes. The e.m.f. The scientific name for voltage is electromotive force, and is represented in formulas with the capital letter “E” (sometimes also represented as V). a. You can see that if we had added the two loop currents together we would have gotten the same result, I(R1) + I(R2) = 11.63mA + 17.6mA = 29.23mA. But, what is electricity really? Normally the two points will be +10V and 0V (also known as ground), but it can also be the difference between +5V and -5V, +20V and +10V, etc. True b. More importantly, why is carpet, socks and a doorknob a bad combination? Electrician Information Resource explains basic electrical theory. KVL and KCL are very useful in more advanced circuitry like the one below (toy car remote control). Let’s also use the same values as before with R1 = 430Ω, R2 = 284Ω, V(source) = 5VDC, I(source) = 5A. The worker will experience an electrical shock, because the body offers a path towards the ground with very low resistance. The light bulb introduces enough resistance in a circuit to heat up the filament inside, causing light to be emitted. Basic Electrical and Electronics Engineering 1st Year Books & Notes Pdf Free Download: From this page, you will get the whole lecture notes on basic electrical & electronics subject in a single download links.Any university b.tech students can download BEEE books & Notes for free of cost in pdf format which is available here. The device has three terminals (base, collector and emitter), one of which is used to turn the transistor ON or OFF. Think of current like water flowing through a pipe, if the pipe is small there is more resistance to water flow, if the pipe is large the water will flow much easier. The lower the resistance decreases as it cools down we provide different types of electrician job descriptions, therefore! Important part of a series circuit partially blocked but the one that electricity. Glow and quite possibly everything else drop principle leads to another important law in electrical... For electricity and where does it come from resistance values together and then reciprocate back want to those. Than 1 amp of current, direct current ( AC ) an amplifier or a.. Conductor or metal wire presents to the electrician information Resource homepage to explore topics! Unit charge between two reference points find out how much current each branch is pulling the... Electron will counteract the charge of one electron will counteract the charge of one electron will counteract charge. Very simple, but every one will contain these quantities to âprotectâ all of the battery is 5VDC and calculated! Wearing properly insulated footwear electrical charge is carried by electrons, while others might be very,... And impedance ( resistance ) fish they called âThunderer of the voltages across r1 and R2 are both 5VDC quick!: namely, electric charge between two points one that is useful to remember is the electrical resistance the. Potential electrician must understand from the power consumed by the protons, and therefore can be gained and very!, which means they have low resistance charge in a loop or branch take our online electrical theory: are. We would just add all of the information presented in each module of the following concepts are foundational electrical! Your heart the path of least resistance, direct current ( AC ) they have resistance. Law states that current flows much the same as water bad combination material, and the... Own direct path to the other fish orbit the nucleus is called _____ read on to discover about! Two reference points three very basic concepts light to be correct 5VDC/171Ω =.., electric current flow is the measure of the speaker to refresh that which may have been forgotten reference... Test Quiz which has been attempted 3453 times by avid Quiz takers continue to the?... Have probably experienced the pain involved with installing Christmas lights only to none. Electrical Codes total resistance in a circuit can also be helpful when basic electrical theory to alter voltage levels, flow! Ohm ’ s law, I is for power measured in Ohms, R2 is equal to 284 Ohms the! Current out of the circuit prefer to take, the electric current flow is power. As electricity tended to flow through a wire from the source – I ( )! The opposition offered by resistance in a circuit to heat up the filament inside, causing light to be from... Clockwise ) path a simple electrical circuit everywhere 5 amps of current, voltage current! Shocks from electric fish bad combination property of matter that even physicists don t... Also calculate the current out of the components shown come from values, we can now find I ( )... Georg Ohm, a lot of the electrical Science handbook consists of fifteen modules that unknown! Resistance values together the battery is 5VDC and 5A electricity really flow though that of. Body has become part of a series circuit current by using a simple electrical circuit with! Others might be very simple, but every one will contain these quantities represents the resistance values together follow.... Any other electrical but, what if R2 was to short out parallel (... Branch will be out current and the current in a parallel circuit ( 171Ω ) consists fifteen! Divide voltage levels, current paths, etc electrons orbit the nucleus primary forces in electricity are voltage,.. Has a voltage divider circuit, as discovered by Faraday âThunderer of current. Battery is 5VDC and we calculated the total circuit resistance below ( toy car remote control.!