What is a Multimeter?

Ohm’s Law defines the essential link between voltage, current, and resistance in electrical circuits. It provides the foundation for circuit design, accurate troubleshooting, and safe operation in both AC and DC systems, making it a core principle of electrical engineering.

What is Ohm’s Law?

Ohm’s Law is a fundamental principle of electrical engineering and physics, describing how voltage, current, and resistance interact in any circuit.

✅ Defines the relationship between voltage, current, and resistance

✅ Provides formulas for design, safety, and troubleshooting

✅ Essential for understanding both AC and DC circuits

When asking what is Ohm’s Law, it is useful to compare it with other fundamental rules like Kirchhoff’s Law and Ampere’s Law, which expand circuit analysis beyond a single equation.

What is Ohm's Law as a Fundamental Principle

Ohm's Law is a fundamental principle in electrical engineering and physics, describing the relationship between voltage, current, and resistance in electrical circuits. Engineers can design safe and efficient electrical circuits by understanding this principle, while technicians can troubleshoot and repair faulty circuits. The applications are numerous, from designing and selecting circuit components to troubleshooting and identifying defective components. Understanding Ohm's Law is essential for anyone working with electrical circuits and systems.

Who was Georg Ohm?

Georg Simon Ohm, born in 1789 in Erlangen, Germany, was a physicist and mathematician who sought to explain the nature of electricity. In 1827, he published The Galvanic Circuit Investigated Mathematically, a groundbreaking work that defined the proportional relationship between voltage, current, and resistance. Though his research was initially dismissed, it later became recognized as one of the cornerstones of modern electrical science.

His work introduced key concepts such as electrical resistance and conductors, and his law became fundamental to circuit design and analysis. The scientific community honored his contribution by naming the unit of resistance — the ohm (Ω) — after him. Today, every student and professional who studies electricity carries his legacy forward.

Georg Simon Ohm

What is Ohm’s Law Formula

At the heart of the law is a simple but powerful equation:

V = I × R

• V is voltage, measured in volts (V)

• I is current, measured in amperes (A)

• R is resistance, measured in ohms (Ω)

Rearranging the formula gives I = V/R and R = V/I, making it possible to solve for any unknown value when the other two are known. This flexibility allows engineers to calculate required resistor values, predict circuit performance, and confirm safe operating conditions.

In both DC and AC systems, the law provides the same basic relationship. In AC, where current and voltage vary with time, resistance is replaced with impedance, but the proportional link remains the same.

The Ohm’s Law equation explains how the amount of electric current flowing through a circuit depends on the applied voltage and resistance. Current is directly proportional to voltage and inversely proportional to resistance, illustrating how electrical charge flows under various conditions. To maintain consistency in calculations, the law employs standard units: volts (V) for voltage, amperes (A) for current, and ohms (Ω) for resistance. Since Ohm’s Law formula defines the relationship between these values, it directly connects to related concepts such as electrical resistance and voltage.

Understanding the Formula

The strength of Ohm’s Law lies in its versatility. With just two known values, the third can be calculated, turning raw measurements into useful information. For an engineer, this might mean calculating the resistor needed to protect a sensitive device. For a technician, it may indicate whether a failing motor is caused by excess resistance or a low supply voltage.

How the Formula Works in Practice

Consider a simple example: a 12-volt battery connected to a 6-ohm resistor. Using the law, the current is I = V/R = 12 ÷ 6 = 2 amperes. If resistance doubles, the current halves. If the voltage increases, the current rises proportionally.

In practical terms, Ohm’s Law is used to:

• calculate resistor values in electronic circuits,

• verify safe current levels in wiring and equipment,

• determine whether industrial loads are drawing excessive power,

• troubleshoot faults by comparing measured and expected values.

Each of these tasks depends on the same simple equation first described nearly two centuries ago. Applying Ohm’s Law often involves calculating current in DC circuits and comparing it with alternating current systems, where impedance replaces simple resistance.

Modern Applications of Ohm’s Law

Far from being outdated, Ohm’s Law remains central to modern technology. In electronics, it ensures safe current levels in devices from smartphones to medical equipment. In renewable energy, it governs the design and balance of solar panels and wind turbines. In automotive and electric vehicle systems, battery management and charging depend on accurate application of the law. Even in telecommunications, it ensures signals travel efficiently across cables and transmission lines. In power engineering, Ohm’s Law works alongside Watts Law and power factor to determine efficiency, energy use, and safe operating conditions.

These examples demonstrate that the law is not a relic of early science but an active tool guiding the design and operation of contemporary systems.

Resistance, Conductivity, and Real-World Limits

Resistance is a material’s opposition to current flow, while conductivity — its inverse — describes how freely charge moves. Conductors, such as copper and aluminum, are prized for their high conductivity, while insulators, like rubber and glass, prevent unwanted current flow.

In reality, resistance can change with temperature, pressure, and frequency, making some devices nonlinear. Semiconductors, diodes, and transistors do not always follow Ohm’s Law precisely. In AC systems, resistance expands to impedance, which also considers inductance and capacitance. Despite these complexities, the proportional relationship between voltage and current remains an essential approximation for analysis and design. Exploring basic electricity and related principles of electricity and magnetism shows why Ohm’s Law remains a cornerstone of both theoretical study and practical engineering.

Frequently Asked Questions

What is an example of Ohm's Law?

A simple example in action is a circuit consisting of a battery, a resistor, and a light bulb. If the voltage supplied by the battery increases, the current flowing through the circuit will also increase, causing the light bulb to glow brighter. Conversely, if the resistance of the circuit is increased by adding another resistor, the current flowing through the circuit will decrease, causing the light bulb to dim.

What are the three formulas in Ohm's Law?

The three formulas are I = V/R, V = IR, and R = V/I. These formulas can solve a wide range of problems involving electrical circuits.

Does Ohm’s Law apply to all electrical devices?

Not always. Devices such as diodes and transistors are nonlinear, meaning their resistance changes with operating conditions. In these cases, Ohm’s Law provides only an approximation.

When asking What is Ohm’s Law, it becomes clear that it is far more than a formula. It is the framework that makes electricity predictable and manageable. By linking voltage, current, and resistance, it offers a universal foundation for design, troubleshooting, and innovation. From the earliest experiments to today’s electronics and power grids, Georg Ohm’s insight remains as relevant as ever.

Related Articles

• Electricity Fundamentals

• Electricity Questions

• Electricity History

Electricity is the flow of electric charge, usually through a conductor like wire. It powers lights, appliances, and machines by converting energy into motion, heat, or light. Electricity can be generated from sources such as fossil fuels, wind, solar, or water.

What is electricity?

Electricity is a fundamental form of energy created by the movement of electrons.

✅ Powers homes, industries, and electronic devices

✅ Flows through circuits as an electric current

✅ Generated from renewable and non-renewable sources

The power we use is a secondary energy source because it is produced by converting primary energy sources such as coal, natural gas, nuclear, solar, and wind energy into electrical power. It is also referred to as an energy carrier, meaning it can be converted into other forms of energy, such as mechanical or thermal energy.

Primary energy sources are either renewable or nonrenewable, but our power is neither.

To understand why electrons move in the first place, start with voltage, the electrical “pressure” that pushes charge through every circuit.

Electricity Has Changed Everyday Life

Although most people rarely think about electricity, it has profoundly changed how we live. It is as essential as air or water, yet we tend to take it for granted—until it’s gone. Electricity powers heating and cooling systems, appliances, communications, entertainment, and modern conveniences that past generations never imagined.

Before widespread electrification began just over a century ago, homes were lit with candles or oil lamps, food was cooled with ice blocks, and heating was provided by wood- or coal-burning stoves.

The steady stream of electrons we use daily is explored in our primer on current electricity.

Discovering Electricity: From Curiosity to Power Grid

Scientists and inventors began unlocking the secrets of electricity as early as the 1600s. Over the next few centuries, their discoveries built the foundation for the electric age.

Benjamin Franklin demonstrated that lightning is a form of electricity.

Thomas Edison invented the first commercially viable incandescent light bulb.

Nikola Tesla pioneered the use of alternating current (AC), which enabled the efficient transmission of electricity over long distances. He also experimented with wireless electricity.

Curious why Tesla’s ideas beat Edison’s? Our article on alternating current breaks down the advantages of alternating current (AC) over direct current (DC).

Before Tesla’s innovations, arc lighting used direct current (DC) but was limited to outdoor and short-range applications. His work made it possible for electricity to be transmitted to homes and factories, revolutionizing lighting and industry.

Understanding Electric Charge and Current

Electricity is the movement of electrically charged particles, typically electrons. These particles can move either statically, as in a buildup of charge, or dynamically, as in a flowing current.

All matter is made of atoms, and each atom consists of a nucleus with positively charged protons and neutral neutrons, surrounded by negatively charged electrons. Usually, the number of protons and electrons is balanced. But when that balance is disturbed—when electrons are gained or lost—an electric current is formed as those electrons move.

For a step-by-step walkthrough of everything from circuits to safety, visit how electricity works.

Electricity as a Secondary Energy Source

Electricity doesn’t occur naturally in a usable form. It must be generated by converting other types of energy. In fact, electricity is a manufactured product. That’s why electricity is called a secondary energy source—it carries energy from its original form to where we need it.

We generate electricity by transforming mechanical energy—such as spinning a turbine—into electrical energy. This conversion happens at power plants that use a variety of fuels and methods:

• Fossil fuels (coal, oil, natural gas)

• Nuclear energy

• Renewable sources like wind, solar, and hydroelectric

If turbines, magnets, and power plants intrigue you, see how electricity is generated for a deeper dive.

How Electricity Was Brought Into Homes

Before electricity generation began on a mass scale, cities often developed near waterfalls, where water wheels powered mills and machines. The leap from mechanical energy to electrical energy enabled power to travel not just across a town, but across entire countries.

Beginning with Franklin’s experiments and followed by Edison’s breakthrough with indoor electric light, the practical uses of electricity expanded rapidly. Tesla’s AC power system made widespread electric distribution feasible, bringing light, heat, and industry to homes and cities worldwide.

How Transformers Changed Everything

To transmit electricity efficiently over long distances, George Westinghouse developed the transformer. This device adjusts the voltage of electrical power to match its purpose—high for long-range travel, low for safe use in homes.

Transformers made it possible to supply electricity to homes and businesses far from power plants. The electric grid became a coordinated system of generation, transmission, distribution, and regulation.

Even today, most of us rarely consider the complexity behind our wall sockets. But behind every outlet lies a vast infrastructure keeping electricity flowing safely and reliably.

How Is Electricity Generated?

Electric generators convert mechanical energy into electricity using the principles of magnetism. When a conductor—such as a coil of wire—moves through a magnetic field, an electric current is induced.

In large power stations, turbines spin magnets inside massive generators. These turbines are driven by steam, water, or wind. The rotating magnet induces small currents in the coils of wire, which combine into a single continuous flow of electric power.

Discover the principle that turns motion into power in electromagnetic induction, the heart of every modern generator.

Measuring Electricity

Electricity is measured in precise units. The amount of power being used or generated is expressed in watts (W), named after inventor James Watt.

• One watt is a small unit of power; 1,000 watts equal one kilowatt (kW).

• Energy use over time is measured in kilowatt-hours (kWh).

• A 100-watt bulb burning for 10 hours uses 1 kWh of electricity.

These units are what you see on your electric bill. They represent how much electricity you’ve consumed over time—and how much you’ll pay.

When it’s time to decode your energy bill, the chart in electrical units makes watts, volts, and amps clear.

Related Articles

• Electricity Fundamentals

• Electricity Questions

• Electricity History

Capacitance is the ability of a component to store electrical charge between plates separated by insulation, measured in farads. It is vital in circuits, electronics, and energy storage for voltage regulation, stability, and efficient power system performance.

What is Capacitance?

Capacitance is a fundamental concept in electrical engineering and physics, describing a system's ability to store energy in the form of an electrical charge.

✅ Measures the ability to store electric charge in a circuit

✅ Essential in filtering, timing, and power conditioning

✅ Found in capacitors used in electronics, motors, and power supplies

Capacitance (C = Q / V) measures the amount of electric charge (Q) a system stores per volt (V); unit: farad (F).

Power Quality Analysis Training

Power Factor Training

Request a Free Power Quality Training Quotation

Capacitance is the property of a system that allows it to store electric charge when a voltage, or electric potential difference, is applied across its terminals. This stored charge represents the system’s charge storage capacity, which is directly proportional to the capacitance value and the applied voltage. In alternating current (AC) circuits, capacitors do not pass current in the same way resistors do; instead, they oppose changes in voltage through a phenomenon known as capacitive reactance. This reactance decreases as the frequency of the AC signal increases, making capacitors essential in filtering, tuning, and timing applications. To understand how stored charge behaves across voltage differences, refer to our guide on capacitive load, which explores how capacitors affect AC circuits. For a detailed breakdown of how capacitance is measured, check out the unit of capacitance to understand farads and their practical conversions.

What Determines Capacitance?

The capacitance of a capacitor is determined by its geometry and the properties of the dielectric material between the conductive plates. The unit of capacitance is the farad, which can be measured in farads. Capacitors are often rated in microfarads (μF) or picofarads (pF), depending on their size and intended use.  For the basics of components that store electrical energy, see what is a capacitor to learn how these devices function and their role in circuits.

Learn how stored charge relates to apparent and real power in AC systems by visiting our apparent power vs real power comparison.

When a capacitor is connected to a voltage source, it charges, storing energy as an electrical field between its conductive plates. The amount of energy stored in a capacitor is proportional to its capacitance and the square of the voltage across it. When the voltage source is removed, the capacitor will slowly discharge, releasing the stored energy as an electrical current. Capacitance is also central to power factor optimization—discover how this works with an automatic power factor controller.

RC Circuits: The Role of Capacitance in Charging

A capacitor's charging and discharging behaviour is determined by its capacitance and the properties of the surrounding circuit. For example, in a simple circuit with a resistor and a capacitor, the capacitor will charge up rapidly when first connected to a voltage source. Still, it will then discharge slowly over time as the energy stored in the capacitor is dissipated through the resistor. The time constant of the circuit, which describes the rate at which the capacitor charges and discharges, is determined by the product of the resistance and capacitance of the circuit.

Capacitors are used in various electronic applications, from filtering noise in power supplies to storing energy in flash memory. The capacitance of a capacitor can be tuned by selecting different dielectric materials, changing the geometry of the conductive plates, or adding additional plates in parallel. To explore how capacitors behave when connected end-to-end, visit capacitance in series, which explains the reciprocal formula and voltage behavior.

Dielectric Materials and Their Effect on Capacitance

Dielectric materials are crucial to the operation of capacitors, as they serve as insulators between the conductive plates. The dielectric constant of a material describes its ability to store electrical energy and is a key parameter in determining the capacitance of a capacitor. Dielectric materials can be solid, such as ceramics or plastics, or liquid, such as electrolytes.

Capacitors can store energy in various forms, from high-voltage electrical energy in power supplies to low-voltage electrical energy in portable electronic devices. The energy stored in a capacitor can provide a quick burst of power to a circuit or smooth out variations in a power supply. If you're curious about how capacitors add their values in parallel, the capacitance in parallel page illustrates how capacitances sum directly, enhancing energy storage.

How Capacitance Compares to Resistance and Inductance

Resistance slows down the transfer rate of charge carriers (usually electrons) by "brute force." In this process, some energy is invariably converted from electrical form to heat. Resistance is said to consume power for this reason. Resistance is pre­sent in DC as well as in AC circuits and works the same way for either direct or alternat­ing current. Capacitor performance depends on safe voltage levels; our page on capacitor voltage rating explains these limits in detail.

Inductance impedes the flow of AC charge carriers by temporarily storing the en­ergy as a magnetic field. However, this energy is eventually replenished. For high-capacitance setups in electrical systems, see how banks of capacitors are configured in our capacitor bank overview.

Capacitance impedes the flow of AC charge carriers by temporarily storing the energy as an electric potential field. This energy is given back later, just as it is in an inductor. Capacitance is not generally necessary in pure-DC cir­cuits. However, it can have significance in circuits where DC is pulsating and not steady. If you're studying how capacitance affects reactive energy, visit our breakdown of reactive power formula in electrical circuits.

Capacitance in AC Circuits and Frequency Response

Capacitance, like inductance, can appear unexpectedly or unintentionally. As with inductance, this effect becomes more evident as the ac frequency increases.

Capacitance in electric circuits is deliberately introduced by a device called a capacitor. It was discovered by the Prussian scientist Ewald Georg von Kleist in 1745 and independently by the Dutch physicist Pieter van Musschenbroek at about the same time while investigating electrostatic phenomena. They discovered that electricity generated by an electrostatic machine could be stored for a period and then released. The device, which came to be known as the Leyden jar, consisted of a stoppered glass vial or jar filled with water, with a nail piercing the stopper and dipping into the water. By holding the jar in hand and touching the nail to the conductor of an electrostatic machine, they found that a shock could be obtained from the nail after disconnecting it by touching it with the free hand.

This reaction showed that some of the electricity from the machine had been stored. A simple but fundamental step in the evolution of the capacitor was taken by the English astronomer John Bevis in 1747 when he replaced the water with metal foil, forming a lining on the inside surface of the glass and another covering the outside surface. The interaction of capacitance and system reactance is a key part of understanding power quality, as explained on our reactor reactance in power systems page.

A Visual Thought Experiment: Capacitance Between Metal Plates

Imagine two very large, flat sheets of metal, such as copper or aluminum, that are ex­cellent electrical conductors. Suppose they are each the size of the state of Nebraska and are placed one on top of the other, separated by just a foot of space. What will happen if these two sheets of metal are connected to the terminals of a battery, as shown in Fig. 11-1?

Fig. 11-1. Two plates will become charged electrically, one positively and the other nega­tively.

The two plates will become charged electrically, one positively and the other nega­tively. You might think this would take a little while because the sheets are so big. However, this is a reasonable assumption.

If the plates were small, they would both become charged almost instantly, attaining a relative voltage equal to the battery's voltage. But because the plates are gigantic, it will take a while for the negative one to "fill up" with electrons, and it will take an equal amount of time for the other one to get electrons "sucked out." Finally, however, the volt­age between the two plates will be equal to the battery voltage, and an electric field will exist in the space between the plates.

This electric field will be small at first; the plates don't charge immediately. However, the negative charge and the positive charge will increase over time, depending on the size of the plates and the distance between them. Figure 11-2 is a relative graph showing the in­tensity of the electric field between the plates as a function of time elapsed since the plates are connected to the battery terminals.

Fig. 11-2. Relative electric field intensity, as a function of time, between two metal plates connected to a voltage source. 

Related Articles

• Power Quality Channel

• Electricity Fundamentals

• Electricity Questions

• Electricity History

Inductance
Michael Faraday discovered that by moving a magnet through a coil of wire, a voltage was induced across the coil. If a complete circuit was provided, then a current was also induced. The amount of induced voltage is directly proportional to the rate of change of the magnetic field with respect to the coil. The simplest of experiments can prove that when a bar magnet is moved through a coil of wire, a voltage is induced and can be measured on a voltmeter. This is commonly known as Faraday’s Law or the law of electromagnetic induction, which states:

The induced emf or electromagnetic force in a closed loop of wire is proportional to the rate of change of the magnetic flux through a coil of wire.

Conversely, current flowing through a coil of wire produces a magnetic field. When this wire is formed into a coil, it then becomes a basic inductor. The magnetic lines of force around each loop or turn in the coil effectively add to the lines of force around the adjoining loops. This forms a strong magnetic field within and around the coil. Figure 1A, illustrates this idea of a coil of wire strengthening a magnetic field. The magnetic lines of force around adjacent loops are deflected into an outer path when the loops are brought close together. This happens because the magnetic lines of force between adjacent loops are in opposition with each other. The total magnetic field for the two loops close together, the strength of the magnetic field will increase. Figure 10-118C illustrates the combined effects of many loops of a coil. The result is a strong electromagnet.

Fig. 1 - Many loops of a coil.

The primary aspect of the operation of a coil is its property to oppose any change in current through it. This property is called inductance. When current flows through any conductor, a magnetic field starts to expand from the center of the wire. As the lines of magnetic force grow outward through the conductor, they induce an emf in the conductor itself. The induced voltage is always in the direction opposite to the direction of the current flow. The effects of this countering emf are to oppose the immediate establishment of the maximum current. This effect is only a temporary condition. Once the current reaches a steady value in the conductor, the lines of magnetic force will no longer be expanding and the countering emf will no longer be present.

At the starting instant, the countering emf nearly equals the applied voltage, resulting in a small current flow. However, as the lines of force move outward, the number of lines cutting the conductor per second becomes progressively smaller, resulting in a diminished counter emf. Eventually, the counter emf drops to zero and the only voltage in the circuit is the applied voltage and the current is at its maximum value.

The RL Time Constant

Because the inductors basic action is to oppose a change in its current, it then follows that the current cannot change instantaneously in the inductor. A certain time is required for the current to make a change from one value to another. The rate at which the current changes is determined by a time constant represented by the greek letter tau (τ). The time constant for the RL circuit is:

In a series RL circuit, the current will increase to 63% of its full value in 1 time constant after the circuit is closed. This build up of course is similar to the build up of voltage in a capacitor when charging an RC circuit. Both follow an exponential curve and reach 99% value after the 5th time constant. Figure 2 illustrates this characteristic.

Physical Parameters
Some of the physical factors that affect inductance are:

1. The number of turns: Doubling the number of turns in a coil will produce a field twice as strong, if the same current is used. As a general rule, the inductance varies as the square of the number of turns.
2. The cross-sectional area of the coil: The inductance of a coil increases directly as the cross-sectional area of the core increases. Doubling the radius of a coil increases the inductance by a factor of four.
3. The length of a coil: Doubling the length of a coil, while keeping the same number of turns, halves the value of inductance.
4. The core material around which the coil is formed: Coils are wound on either magnetic or nonmagnetic materials. Some nonmagnetic materials include air, copper, plastic, and glass. Magnetic materials include nickel, iron, steel, or cobalt, which have a permeability that provides a better path for the magnetic lines of force and permit a stronger magnetic field. 

Self-Inductance
The characteristic of self-inductance was summarized by German physicist Heinrich Lenz in 1833 and gives the direction of the induced electromotive force (emf) resulting from electromagnetic induction. This is commonly known as Lenz’s Law, which states:

"The emf induced in an electric circuit always acts in such a direction that the current it drives around a closed circuit produces a magnetic field which opposes the change in magnetic flux."

Self inductance is the generation of a voltage in an electric circuit by a changing current in the same circuit. Even a straight piece of wire will have some degree of inductance because current in a conductor produces a magnetic field. When the current in a conductor changes direction, there will be a corresponding change in the polarity of the magnetic field around the conductor. Therefore, a changing current produces a changing magnetic field around the wire.

To further intensify the magnetic field, the wire can be rolled into a coil, which is called an inductor. The changing magnetic field around the inductor induces a voltage across the coil. This induced electromotive force is called self-inductance and tends to oppose any change in current within the circuit. This property is usually called inductance and symbolized with the letter L. 

A conductor is a material that allows electric current to flow easily due to its low resistance. Common conductors include copper and aluminum, used in electrical wiring and components. Conductors play a critical role in power distribution and circuit functionality.

What is a Conductor?

A conductor enables the flow of electricity or heat with minimal resistance. It's essential in electrical systems.

✅ Transfers electricity efficiently, commonly using copper or aluminum

✅ Used in wiring, power grids, and electronics

✅ Minimizes resistance for stable current flow

Understanding what a conductor is and how it functions is crucial to comprehending various aspects of modern life, including electricity, thermal management, and electronics. Conductors facilitate the flow of electrons and heat in various applications, while insulators impede these movements. Due to their unique properties and availability, copper, silver, and aluminum are good conductors of electricity. As a result, they are among the most commonly used conductor materials because they facilitate the flow of electricity. Factors affecting conductivity include atomic structure, temperature, and the purity of the material.

Conductors are an integral part of our daily lives, enabling the functioning of various devices and systems we depend on, such as electrical wiring and electronic devices. In contrast, thermal conductors facilitate heat transfer in numerous applications, from car engines to cookware. In addition, the unique category of semiconductors demonstrates that a material can possess both conductive and insulating properties, paving the way for the development of advanced technologies such as transistors and solar cells.

The Role of Conductors in Electricity

A conductor plays an essential role in the world of electricity. It enables the movement of electrons within a material, allowing electrical charge to flow smoothly through an electrical circuit. Electrical conductors consist of atoms that have loosely bound electrons, which are free to move and generate a current when an electric field is applied. This phenomenon is the basis for the flow of electrons in many electrical devices and systems.

Conductors and Insulators: The Key Differences

The primary difference between conductors and insulators lies in their ability to conduct electricity. While conductors, which are solid in nature, allow the flow of electrons, insulators impede this flow due to their tightly bound electrons. Consequently, insulators prevent electric shock or maintain electrical charge within specific boundaries. Good insulators include rubber, plastic, and glass.

Common Conductor Materials

The most commonly used materials for electrical conductors include copper, silver, and aluminum. Copper conductors are often preferred due to their excellent conductivity, relatively low cost, and high availability. Silver possesses the highest conductivity but is more expensive and less abundant. Aluminum is lightweight and affordable, making it an attractive choice for various applications such as power lines.

Factors Affecting Conductivity

The conductivity of a material depends on several factors, including its atomic structure, temperature, and purity. Materials with more free electrons or a regular atomic arrangement are more conducive. Temperature can also influence conductivity, as higher temperatures may cause the atoms in a material to vibrate more, leading to increased resistance. Purity is another essential factor, as impurities can impede the flow of electrons, reducing conductivity.

Applications of Conductors in Everyday Life

Conductors play a vital role in our daily lives, providing the foundation for many devices and systems that rely on the movement of electrons. Some notable examples include electrical wiring, power lines, and electronic devices such as computers and smartphones. Additionally, conductors are used in protective gear like fire-resistant clothing, which incorporates metal fibers to dissipate heat from the body.

Thermal Conductors: Function and Use

Thermal conductors allow heat to flow through them, effectively conducting heat from one area to another. This process is essential in many applications, such as in car engines, where conductors help dissipate heat away from the engine to prevent overheating. Thermal conductors are also found in household items, such as pots and pans, where heat must be transferred evenly for efficient cooking.

Can a Material be Both a Conductor and an Insulator?

In some cases, the material can exhibit both conductive and insulating properties. These materials are known as semiconductors, which possess a conductivity level between conductors and insulators. Silicon and germanium are two common examples of semiconductors. Semiconductors have numerous applications in electronic devices, including transistors and solar cells, which can regulate electrical current and convert sunlight into electricity.

As our understanding of conductors and their properties expands, we anticipate further innovations and improvements in the materials used in these essential components. For example, new conductor materials and composites could potentially be developed, offering better performance, higher efficiency, or enhanced durability. These advancements will contribute to the creation of even more sophisticated technologies and further enhance the quality of our everyday lives.

Related Articles

• Electricity Fundamentals

• Electricity Questions

• Electricity History

Who discovered electricity? Early pioneers including William Gilbert, Benjamin Franklin, Luigi Galvani, Alessandro Volta, and Michael Faraday advanced static electricity, circuits, and electromagnetism, laying the foundation for modern electrical science.

Who Discovered Electricity?

No single person discovered electricity; figures Gilbert, Franklin, Galvani, Volta and Faraday shaped the field.

✅ William Gilbert coined "electricus"; foundational studies of magnetism.

✅ Franklin's kite experiment linked lightning and electricity; charge theory.

✅ Volta's pile enabled current; Faraday unified electromagnetism.

Who Discovered Electricity ? From the writings of Thales of Miletus it appears that Westerners in their day knew as long ago as 600 B.C. that amber becomes charged by rubbing. But other than that, there was little real progress until the English scientist William Gilbert in 1600 described the electrification of many substances and coined the term "electricity" from the Greek word for amber. For a deeper look at how ideas about discovery versus invention evolved, see who invented electricity for historical perspective.

As a result, Gilbert is called the father of modern electric power. In 1660, Otto von Guericke invented a crude machine for producing static electricity. It was a ball of sulfur, rotated by a crank with one hand and rubbed with the other. Successors, such as Francis Hauksbee, made improvements that provided experimenters with a ready source of static electricity. Today's highly developed descendant of these early machines is the Van de Graaf generator, which is sometimes used as a particle accelerator. Robert Boyle realized that attraction and repulsion were mutual and that electric force was transmitted through a vacuum. Stephen Gray distinguished between conductors and nonconductors. C. F. Du Fay recognized two kinds of power, which Benjamin Franklin and Ebenezer Kinnersley of Philadelphia, peoples who later named positive and negative.

For a quick chronological overview of these pioneering advances, consult this timeline of electricity to trace developments across centuries.

Progress quickened after the Leyden jar was invented in 1745 by Pieter van Musschenbroek. The Leyden jar stored static electricity, which could be discharged all at once. In 1747 William Watson discharged a Leyden jar through a circuit, and comprehension of the current and circuit started a new field of experimentation. Henry Cavendish, by measuring the conductivity of materials (he compared the simultaneous shocks he received by discharging Leyden jars through the materials), and Charles A. Coulomb, by expressing mathematically the attraction of electrified bodies, began the quantitative study of electric power. For additional background on early experiments and theory, explore the history of electricity for context and sources.

Depite what you have learned, Benjamin Franklin did not "discover" electric power. In fact, electric power did not begin when Benjamin Franklin at when he flew his kite during a thunderstorm or when light bulbs were installed in houses all around the world. For details on why Franklin is often miscredited, read did Ben Franklin discover electricity for clarification.

The truth is that electric power has always been around because it naturally exists in the world. Lightning, for instance, is simply a flow of electrons between the ground and the clouds. When you touch something and get a shock, that is really static electricity moving toward you. If you are new to the core concepts, start with basic electricity to ground the fundamentals.

Power Personalities

Benjamin Franklin

Ben Franklin was an American writer, publisher, scientist and diplomat, who helped to draw up the famous Declaration of Independence and the US Constitution. In 1752 Franklin proved that lightning and the spark from amber were one and the same thing. The story of this famous milestone is a familiar one, in which Franklin fastened an iron spike to a silken kite, which he flew during a thunderstorm, while holding the end of the kite string by an iron key. When lightening flashed, a tiny spark jumped from the key to his wrist. The experiment proved Franklin's theory. For more about Franklin's experiments, see Ben Franklin and electricity for experiment notes and legacy.

Galvani and Volta

In 1786, Luigi Galvani, an Italian professor of medicine, found that when the leg of a dead frog was touched by a metal knife, the leg twitched violently. Galvani thought that the muscles of the frog must contain electric signals. By 1792 another Italian scientist, Alessandro Volta, disagreed: he realised that the main factors in Galvani's discovery were the two different metals - the steel knife and the tin plate - apon which the frog was lying. Volta showed that when moisture comes between two different metals, electric power is created. This led him to invent the first electric battery, the voltaic pile, which he made from thin sheets of copper and zinc separated by moist pasteboard.

In this way, a new kind of electric power was discovered, electric power that flowed steadily like a current of water instead of discharging itself in a single spark or shock. Volta showed that electric power could be made to travel from one place to another by wire, thereby making an important contribution to the science of electricity. The unit of electrical potential, the Volt, is named after Volta.

Michael Faraday

The credit for generating electric current on a practical scale goes to the famous English scientist, Michael Faraday. Faraday was greatly interested in the invention of the electromagnet, but his brilliant mind took earlier experiments still further. If electricity could produce magnetism, why couldn't magnetism produce electric power.

In 1831, Faraday found the solution. Electricity could be produced through magnetism by motion. He discovered that when a magnet was moved inside a coil of copper wire, a tiny electric current flows through the wire. Of course, by today's standards, Faraday's electric dynamo or electric generator was crude, and provided only a small electric current be he discovered the first method of generating electric power by means of motion in a magnetic field.

Thomas Edison and Joseph Swan

Nearly 40 years went by before a really practical DC (Direct Current) generator was built by Thomas Edison in America. Edison's many inventions included the phonograph and an improved printing telegraph. In 1878 Joseph Swan, a British scientist, invented the incandescent filament lamp and within twelve months Edison made a similar discovery in America. For a broader view of his role in power systems, visit Thomas Edison and electricity for projects and impact.

Swan and Edison later set up a joint company to produce the first practical filament lamp. Prior to this, electric lighting had been my crude arc lamps.

Edison used his DC generator to provide electricity to light his laboratory and later to illuminate the first New York street to be lit by electric lamps, in September 1882. Edison's successes were not without controversy, however - although he was convinced of the merits of DC for generating electricity, other scientists in Europe and America recognised that DC brought major disadvantages.

George Westinghouse and Nikola Tesl

Westinghouse was a famous American inventor and industrialist who purchased and developed Nikola Tesla's patented motor for generating alternating current. The work of Westinghouse, Tesla and others gradually persuaded American society that the future lay with AC rather than DC (Adoption of AC generation enabled the transmission of large blocks of electrical, power using higher voltages via transformers, which would have been impossible otherwise). Today the unit of measurement for magnetic fields commemorates Tesla's name.

James Watt

When Edison's generator was coupled with Watt's steam engine, large scale electricity generation became a practical proposition. James Watt, the Scottish inventor of the steam condensing engine, was born in 1736. His improvements to steam engines were patented over a period of 15 years, starting in 1769 and his name was given to the electric unit of power, the Watt.

Watt's engines used the reciprocating piston, however, today's thermal power stations use steam turbines, following the Rankine cycle, worked out by another famous Scottish engineer, William J.M Rankine, in 1859.

Andre Ampere and George Ohm

Andre Marie Ampere, a French mathematician who devoted himself to the study of electricity and magnetism, was the first to explain the electro-dynamic theory. A permanent memorial to Ampere is the use of his name for the unit of electric current.

George Simon Ohm, a German mathematician and physicist, was a college teacher in Cologne when in 1827 he published, "The galvanic Circuit Investigated Mathematically". His theories were coldly received by German scientists but his research was recognised in Britain and he was awarded the Copley Medal in 1841. His name has been given to the unit of electrical resistance.

Go here to visit all of our Electrical Energy pages.

Related Articles

• Electricity Fundamentals

• Electricity Questions

• Electricity History