Coulomb, Volta, Ampere and Ohm’s Contributions in The Electrical Theory IntroductionElectricity is a term used to describe a variety of physical phenomena due to the presence and flow of electric charges. Its discovery dates back from ancient Greek and Parthian civilizations. Many scientists have tried to understand these phenomena. They did extensive research and one discovery leads after another.Many scientists studied electricity and were able to develop the electric theory.
The most notable names in this field are Charles Coulomb, Andre Ampere, Alessandro Volta, and George Simon Ohm.The development of this theory led to many inventions that made human lives easier.ElectricityElectricity is the phenomenon associated with the presence and flow of electric charges in a circuit. This word was derived from the Greek word elektron which means amber. Greeks discovered that when amber is rubbed with a fur, it is able to attract light objects such as feathers. William Gilbert, an English scientist, derived the term electricity from the Greek word for amber. He is also called the father of modern electricity.
Static electricity is the first electrical phenomena to be studied. The amber phenomenon is mainly due to static charges in the fur. When the amber was rubbed into the fur, it became charged and it was able to attract light objects.The term electricity is used in several related concepts that are vital parts of the electric theory. These concepts are usually identified by these terms: electric potential, electric current, electric field, electric energy, electric power, and electric charge.Basic electrical theory made greater impact on the importance of electricity in the modern society.
The basic electrical theory includes static electricity, electrical power, electric current, electric resistance, and electromotive force. Static electricity is an electric charge that builds up in an object which can be produced by friction. Electrical power is the rate of doing electrical work measured in watts.
Electric current is the flow of electric charge through a conductor per second; the unit used is Ampere. Electric resistance is the opposition of a material to current flow measured in Ohms. Voltage is the difference of electrical potential between the two points of an electrical circuit; measured in volts. History of Electrical TheoryThe oldest written evidence of electrification dates back 600 B.C.
by Thales of Miletus. He wrote that amber, when rubbed with a fur, is able to attract light objects. This knowledge however did not get much interest of the people until English scientist William Gilbert in 1600 AD described the electrification of substances. He also coined the term electricity from the Greek word elekton for amber. Gilbert became the ‘father of modern electricity’.Otto von Guericke invented a machine that produced static electricity in 1660 using a ball of sulfur which is rotated by one hand and rubbed with the other hand. Many successors made improvements in this crude machine developing it into a ready source of static electricity. Guericke’s invention was the ancestor of the Van de Graaf generator made for domestic and industrial use.
In 1785, Charles Augustin de Coulomb was able to invent a device called the torsin balance which could measure electrostatic force. The unit of electricity was named after him. In 1800, Alessandro Volta created the Voltaic cell which consist of 2 electrodes (Zinc and Copper) suspended in a Sulphuric Acid solution.
In 1820, Andre Marie Ampere introduced the laws of electrodynamics. He was able to define the relationship between the direction of electric flow and the deflection of a magnetic needle following Oersted’s announcement of electromagnetism. In 1827, George Simon Ohm did a careful study about the electric current flowing through conductors and ended on the development of a law known as the Ohm’s Law which provided a formula for measuring current.Basic electrical theory became the foundation of many developments in science and technology today.
We experience fast-paced developments all owing to this theory.Charles Augustin de Coulomb (1736-1806),Charles Coulomb invented a device that could measure static electrical force which he called the torsion balance. The balance had two pith balls—one mounted and unmovable and the other is free to roll around. He noted that when the two balls are energized with the same charge (positive or negative), the movable ball roll away from the mounted one.
When the balls are energized with different charges, the movable ball roll towards the mounted one. The distance traveled by the movable ball is used to measure the electrostatic force.One of the three reports on Electricity and Magnetism presented by Coulomb in 1785 came to be the Law of Inverse Squares (Coulomb’s Law): f=k(Q1 x Q2) / d2; f is force, Q1 and Q2 are the charges, d is the distance, and k is a constant. The Law of Inverse Squares states that the ‘force of repulsion is inversely proportional to the square of the distance between the centers of the two spheres.’Coulomb was able to explain the laws of attraction and repulsion of electric charges and magnetic poles, though he was not able to find any relationship between the two.
Attraction and repulsion for him was caused by different kinds of fluids. Today, the SI unit of charge (coulomb) and the Law of Inverse Squares (Coulomb’s law) were named after him.Alessandro Volta and the Voltaic BatteryHe worked as a physics professor in the Como high school in 1774. He’s always interested in the study of electricity and his fascination made him wrote a poem about it.In 1775, he invented a device that produced a static electric charge which he called the Electrophorus which later on became useful in his Voltaic Pile. He also studied chemistry and discovered methane.
He devised many experiments about electricity. One of which is the ignition of gas by an electric spark in a closed vessel.In 1779 he became a Physics professor at the University of Pavia. There he had a professional disagreement with Luigi Galvani and was inspired to repeat Galvani’s experiments. He came to the conclusion that metallic electricity caused the sudden movement in the frog’s leg.However, his metallic electricity cannot explain why the frog’s leg would still jump even if there were no two types of metal. Scientists that time cannot explain this phenomenon so Volta put his efforts on the development of the two metal theory.
In 1800, he unveiled the Voltaic Pile. By using zinc and copper disks placed in alternate position with a brine soaked cloth in between, he was able to create the first direct current battery. It produces a continuous current when a wire is attached to either end. Volta described his battery as an ‘electric organ’ similar to that of the torpedo fish’s electric organ which is made of columnar stacks of cells.
Modern batteries follow Volta’s discoveries. The use of positive and negative electrodes placed in a liquid solution is known as a wet cell. The dry cell is the highly developed form of the Voltaic pile.
The unit of electromotive force is measured in volts named after Alessandro Volta.Andre Marie AmpereAndre Marie Ampere defined the relationship between the direction of electric flow and the deflection of a magnetic needle. He formulated the law of electrodynamics. It states that currents in the same direction attracts each other while opposite currents repel each other. He also suggested that electromagnetism can be used in telegraphy.Ampere used in his measurements a highly sensitive galvanometer—a device used to detect and measure electrical flow.
The two ends of the galvanometer are connected to anything to be tested (such as a battery). If the needle deflects, it means there is electrical current. Stronger current will produce greater deflection in the galvanometer needle. The unit of electric current is called an ampere or amp.
George Simon OhmIn 1825, George Simon Ohm published his researched about the decrease of electromagnetic force when the conductor length is increased. The paper showed mathematical relationships Ohm deducted during his experiments. He published two more important papers in 1826 which were mathematical descriptions of conduction in circuits.
These papers were vital to the completion of his famous book published a year after.In 1827, he published The Galvanic Circuit Investigated Mathematically, a book containing what is now known as Ohm’s Law. Ohm’s Law states that, ‘in an electrical circuit, the current is directly proportionate to the voltage in the current and inversely proportional to the resistance in the current.’ In equation form, this is written as: I = V/R, where I is the current, V potential difference, and R as the resistance. This equation also provided a method of computing for current and voltage. The unit of resistance is called an ohm. ConclusionThe electrical phenomena were explained in the electrical theory.
. The basic electrical theory includes the following:Static electricity – electric charge that builds up in an object which can be produced by frictionElectrical power – the rate of doing electrical work; measured in wattsElectric current – the flow of electric charge through a conductor per second; measure in amperesElectric resistance – the opposition of a material to current flow; measured in ohmsVoltage – the difference of electrical potential between the two points of an electrical circuit; measured in volts Works Cited: (“The History of Electricity”; “Electricity”; “The History of Electricity”; “Charles Augustin De Coulomb”; “Alessandro Volta”; “André-Marie Ampère”; “George Simon Ohm”)”Alessandro Volta”. (7 March 2007): Wikipedia: The Free Encyclopedia. March 7 2007. <http://en.wikipedia.org/wiki/Alessandro_Volta>.
“André-Marie Ampère”. (7 March 2007): Wikipedia: The Free Encyclopedia. March 7 2007. <http://en.wikipedia.
org/wiki/Andre_Marie_Ampere>.”Charles Augustin De Coulomb”. New York University. March 6 2007.
<http://itp.nyu.edu/~nql3186/electricity/pages/coulumb.html>.”Electricity”. (6 March 2007): Wikipedia: The Free Encyclopedia. March 6 2007.
<http://en.wikipedia.org/wiki/Electricity>.”George Simon Ohm”. Hesston College. March 7 2007. <http://www.
hesston.edu/academic/faculty/nelsonk/PhysicsResearch/OhmsLaw/ohmpaperEZ.htm>.”The History of Electricity”. (February 26, 1996): codecheck.com.
March 7 2007. <http://www.codecheck.com/pp_elect.html>.
“The History of Electricity”. (March 1, 2007): Wikipedia: The Free Encyclopedia. March 6 2007. <http://en.wikipedia.org/wiki/History_of_electricity>.