It was well known from at least the antiquity that by rubbing certain materials electrical charge can be created, but for several centuries we did’t have any explanation of this strange phenomena. Systematic experiments with static electricity began not earlier than the 17th century, and became an important subject of entertainers – called electritians – by the 18th century.
Experiments by the silk-trader Stephen Gray spread the fashion of static electricity from the 1740s in Europe. Gray discovered that some materials conduct, while others insulate electric current. At that time electric flow was considered similar to the flow of water, with the exception that it was still impossible to store the misterious energy.
Pieter von Musschenbroek accidentally finds the way to store electrical charge; the Leyden Jar was capable to keep its charge for several days. Despite that conductors and insulators were already at that time, electric charge, electricity became firt transportable by carrying Leyden Jars.
Pieter von Musschenbroek accidentally finds the way to store electrical charge; the Leyden Jar was capable to keep its charge for several days. Despite that conductors and insulators were already at that time, electric charge, electricity became firt transportable by carrying Leyden Jars.
The American Benjamin Franklin proved that thunderbolts are electrical phenomena, thus linking electricity with light. During his experiments with the Leyden jar he discovered the difference between negative and positive charge. He imagined that every conducting body was surrounded by an invisible electric fluid; on the side of positive charge too much electrical fluid is present, while at the negative pole there is a lack of this fluid. And that nature endeavors to balance always (as does the ideal american economy), the two poles attract each other. This is the explanation to why the Leiden bottle is only charged with electricity when you keep it in your hands, which serves as a conductor: the positive charge of the human hand attracts the negative charge, from which the glass of the jar insulates it. This charging negative strain(voltage) cause the electric shock if we touch the conduit on the top of the jar. Contemporary condensators, which is a component of almost every electrical appliance, work exactly the same way, they are the modern miniature versions of the Leyden jar.
With the introduction of the torpedo fish in England a new type of electricity (fundamentally different from static electricity) was discovered. Henry Cavendish aimed to reproduce the amazingly strong electric shock produced by the torpedo fish, and discovers the difference between voltage(electric tension) and amperage (the intensity of electric current).
The fact that living organisms can produce electricity opened a new chapter in investigating the mysterious phenomena. Is this the same electricity what can be produced artificially, which is similar to God’s whip, to the thunderbolt?
In Italy two scientists competed with each other from the distance of 150km, in Bologna and Pavia; the studies of Galvani and Volta were the next important milestones of the history of electricity. Galvani’s approach came from anatomy/autopsy, he concentrated on electrical shocking of dead or paralyzed tissues. He was convinced that living organisms are filled with a completely different kind of electricity from the artificially produceable one, that was planted into every living creature by God.
“In January 1803, the body of the murderer George Forster was pulled from the gallows of Newgate Prison in London and taken to the Royal College of Surgeons. There, before an audience of doctors and curiosity-seekers, Giovanni Aldini, nephew of the late Luigi Galvani, prepared to return the corpse to life.
At least, that is what some of the spectators thought they were witnessing. When Aldini applied conducting rods, connected to a large battery, to Forster’s face, “the jaw began to quiver, the adjoining muscles were horribly contorted, and the left eye actually opened”. The climax of the performance came as Aldini probed Forster’s rectum, causing his clenched fist to punch the air, as if in fury, his legs to kick and his back to arch violently.”
As Volta invented his famous piles, it became possible to examine the phenomenon of electrolysis. The continuous electrical current led to the disintegration of water molecules, caused hydrogen and oxygen precipitation from the water. This started a new chapter in all natural sciences, both in chemistry where new chemical elements could be discovered, but even in physics.
The following step was the discovery of the relationship between electricity and the magnetic field. In 1820 the Danish Hans Christian Ørsted discovers that the electric flow in wires hijacks the compass. Based on Ørsted’s discovery Faraday proves the existence of electromagnetic field and electromagnetic induction.
Faraday essentially created the first electric motor, and the first practical device producing electricity, the Faraday wheel: this homopolar generator was capable to develop electrical current from rotating movement in a magnetic field.
The Faraday disk was the first electric generator (1831). The horseshoe-shaped magnet (A) created a magnetic field through the disk (D). When the disk was turned, this induced an electric current radially outward from the center toward the rim. The current flowed out through the sliding spring contact m, through the external circuit, and back into the center of the disk through the axle.
The coiled electromagnets created by William Sturgeon and Joseph Henry have paved the way for the creation of the first telecommunication medium, the telegraph.
Following the invention of the light bulb, Edison started to set up an electrical network in Manhattan. The direct current (DC), however, can not be transmitted economically over long distances, so the alternating current (AC, invented by Tesla) networks, based on transformators was the real breakthrough.
Maxwell described mathematically the operation of the electric field, what Heinrich Hertz and Oliver Lodge proved by demonstrative practical experiments, besides laying the foundations of the practical use of electromagnetic (radio) waves. Following Lodge, Jagadish Chandra Bose creates the first telegraph which was stolen by Marconi, who patents it and makes money from it. But Bose discovers the advantages of using semiconductor crystals for the detection of radio waves, so practically invents the radio-receiver.
The ancestors of “neon-tubes”, the first vacuum tubes filled with different gases were produced by Johann Heinrich Wilhelm Geissler (1815-1879) from the 1850s. These early cathode-ray tubes were called Geissler-tubes. In these spectacular tubes the contained gases were glowing in various colors as electric current was conducted through them. (Today’s fluorescent tubes and lightbulbs work pretty the same way – it is rather surprising that they were invented decades before Edison’s light bulb.)
Demonstrates kinetic energy. The electrons bounced at the paddles covered with a small amount of phosphor will turn the paddlewheel and move from one to the other side of the tube. In fact it is the heat which is present when the electrons strike the vanes that turns the peddle wheel similar as the Radiometer. Several scientists like Maxwell and Puluj stated this although Crookes was convinced of the electron force theory. Eventually it was Thomson who proved (1903) that the electron force in the tube necessary to move the wheel was insufficient.
This is one of the most famous Crookes tubes. The tube demonstrates that electrons go in a straight line and don’t go through metal. The cross can actually lay down and stand up (mechanically). When the cross lies down, the glass face of the tube emits a green glow when the electrons strike the glass wall, when it’s right up you will see the shadow of the cross. After a while due to fatigue of the glass the glow is less strong, when the cross is tipped over at that time, the previous unexposed glass glows brighter than the surrounding glass.
This nice tube is the first demonstration CRT with a direct heated filament cathode and a Wehnelt cylinder for focussing the electron beam.This tube, probably imported from E Leybolds Nachfolger and sold by W Edwards and co London. Special is the fact that this tube has four static deflection plates.
Transistors, How do they work ?https://www.youtube.com/watch?v=7ukDKVHnac4