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Dynamo:
The dynamo was the first electrical generator that could deliver power and begin an industry of selling electricity. It all started off with Faraday's discovery of electromagnetic induction. Faraday actually created a simple generator that delivered very small amounts of power. It used electromagnetic principles to convert the mechanical rotation in the system into AC or DC current. The dynamo has a stationary structure which generates a strong magnetic field. A set of rotating windings are found in the dynamo and they turn within the dynamo's magnetic field. This “electric generator” simply moves the electric current already present in the conductive wire of its windings. Thomas Edison had the first patent for a dynamo which was called the “long legged Mary-Ann”. Edison's dynamo was used to power lower Manhattan and provided direct current. Edison later improved his dynamo which included an extra coil and it utilized the field of force. The third and very significant patent for the dynamo was Nikola Tesla's alternating current induction motor/generator which eventually revolutionized the electric industry and made it possible to send electric current to long distances.

References:
1) Dynamo - http://en.wikipedia.org/wiki/Electrical_generator
2) Dynamo - http://ieee-virtual-museum.org/collection/tech.php?taid=&id=2345846&lid=1

Transistor:
The transistor is a device that is used to amplify electrical currents. It was invented at the Bell Laboratories by John Bardeen, Walter Brattain, and William Shockley in 1947. Prior to the transistor, electron tubes were used; however, transistors were cheap, small, and efficient and were therefore taken up as a replacement for the electron tubes. Transistors were mainly used in circuits where usually one transistor would be found on the “wafer” or chip. But over time, engineers began placing several transistors on the chip, making the chip more powerful. More and more inventors began to experiment with transistors and tried to put transistors on whole electrical circuits. Two people did succeed in doing so, and they led to the birth of the new silicon chip industry.

References:
1) Transistors - http://ieee-virtual-museum.org/exhibit/exhibit.php?taid=&id=159249&lid=1&seq=13

Arc Lights:
Arc lights were a tool used for lighting, caused by an electric arc between two electrodes. They were first discovered by Humphrey Davy, who was a lecturer of the early 1800s. In 1802, he gave a lecture about how light can be produced by passing electricity through a platinum strip. Then in 1809, he was able to produce a blinding light between two carbon electrodes. Humphrey’s demonstration led to the commercial arc light. Arc lights, however, could not be used indoors. They were extremely flammable and potentially dangerous. Also, they must be held at far distances, because they burned so brightly.

References:
1) Arc lights - http://www.uh.edu/engines/epi1330.htm

Diodes:
A diode “is a component that restricts the directional flow of charge carriers” (Ref. 1). It permits current to flow in only one direction by blocking the reverse direction. Diodes are vital in the creation of circuits that require only one direction for current to flow in. Diodes are commonly made out of semiconductor metals such as silicon or germanium. Diodes can come as thermionic diodes or semiconductors. Thermionic diodes are where an arrangement of electrodes are “surrounded by a vacuum within a glass envelope”. In semiconductor diodes, current can flow from the anode to the cathode, but can not flow in the reverse order.

References:
1) Diodes - http://en.wikipedia.org/wiki/Diode

The Voltaic Pile:
The Voltaic Pile was created by Volta and one of his two famous inventions. It was the first version of the alkaline battery. It is made by taking zinc plates interchanged with copper and silver, and placing them on a rod. In between each piece of metal was a cardboard like material soaked in a saline, which would help with conductivity. A wire is inserted under the disks, and a insulated wire at the top.The top wire has a negative charge, while the wire on the bottom has a positive charge. The battery would only stop working when the saline solution dried up, or the metal dissolved. A giant Voltaic Pile was created in order to find new elements like strontium, calcium and magnesium. With the use of the Voltaic Pile it was able to create a sustained light, and the arc light was created. It was used to create a bluish tinted light by way of the pile and carbon. The light would remain as long as there was power and carbons needed.

References:
Jill Jonnes' Empires of Light

The Leyden Jar: The Leyden jar was the first item capable of storing electricity. It was invented in Leyden, Holland by Professor van Musschenbroek in 1746. The Leyden jar typically consisted of a thin glass container wrapped on the bottom two-thirds of the jar by a metal foil. A metal rod came up out of the jar, through the non-conductive cork lid and was topped by a brass ball. The jar was charged by directing electricity down the metal rod and into the water and foil. The charge would usually hold for several days. Electricity could be drawn be simply touching the brass ball.

References:
1) Jill Jonnes' Empires of Light

Electric Motor (AC and DC): While Joseph Henry and Michael Faraday were working on the electric motor about the same time, Faraday was the first to build a successful electric motor. In 1837, Nicola Tesla invented an electric motor powered by AC current. The idea behind electric motors is that a combined force of magnetism and electricity cause the motor to spin, transferring electric energy into mechanical energy.

References:
1) Jill Jonnes' Empires of Light

Transformers: Michael Faraday first demonstrated the principles of the transformer in 1831. Transformers transfer electric energy from one from one circuit to another. A changing current in the first circuit creates a changing magnetic field. This magnetic field causes a changing voltage in the second circuit. By adding a loadto the second circuit, the current will flow in the transformer, transferring energy from one circuit to the other.
References:
1) Jill Jonnes' Empires of Light

Incandescent Light Bulb: In the 1800’s with advances in electricity many inventors started looking for affordable electrical lighting that could be used inside the home. In 1978 and 1979 Sir Joseph Swan and Thomas Edison independently managed to find a viable solution. Surprisingly these solutions were actually rather simple and haven’t changed much to this very day. Incandescent bulbs consist of a glass bulb which is filled with an inert gas and holds a filament. When electricity is applied to this filament it heats up to temperatures of 4000 degrees. This causes the atoms in the metal of the filament to release a large amount of visible light. The purpose of the inert gas inside the bulb is to prevent combustion of the filament so that it can light without burning up.

References:
1) http://home.howstuffworks.com/light-bulb.htm