PMT_History_Notes Four Developmental Stages
Stage One - The Battery
~1750~ Benjamin Franklin - while experimenting with electricity discovered how to store static electricity into glass and metal containers (now called capacitors), then connected them together to increase the overall discharge, calling the containers a battery, as in a battery of cannons, i.e. increasing their overall effectiveness.
~1780~ Luigi Galvani while dissecting a frog in a solution using a brass hook and an iron scalpel noticed the leg twitched and shared his observation with a friend and fellow scientist Alessandro Volta.
~1800~ Alessandro Volta experimented with different metals and solutions and invented what we now call the storage battery, i.e. battery.
~1938~ Archaeologists discovered an early first century battery in a jar using copper, iron, and common food acid liquid like lemon juice, wine or vinegar, etc. most likely used to electroplating jewelry.
~1800's~ improvements in battery materials and solutions lead into developments in both dry and wet cell batteries including rechargeable batteries.
Stage Two - The Electromagnet
~1825~ William Sturgeon (British) used a single cell battery, a seven ounce piece of iron wrapped in wire, lifted a nine pound metal object , discovering electromagnetism, the first modern day practical use for a battery.
~1830~ Joseph Henry connected a movable metal arm with a striker and bell to a electromagnet and ran wire over one mile and was able to strike the bell. Joseph Henry shared his experiment with others with no intention to patent it.
~1835~ Samuel Morse expanded upon Joseph Henry's experiment and used an electromagnet moving a metal arm with a marker. He next used a moving strip of paper with the maker to write an encoded message, once received could then be decrypted.
Stage Three - Telecommunications
~1835-1845~ Samuel Morse developed the Morse Code after it was discovered that the sound of the moving arm and marker could be understood just by listening and required no decryption. Congress funded an experimental circuit between Washington D.C. and Baltimore and the first message was sent on may 24, 1844, "What hath God wrought!"
~1845-1855~ the teleprinter evolved from a series of inventions to improve faster and more accurate communication over telegraph circuits without using coded sounds.
~1876~ Alexander Graham Bell invented "an improvement of the telegraph", and was later called the telephone by Alexander Graham Bell.
Stage Four - Electric Energy
~1880-1887~ Thomas Edison patented the carbon filament light bulb, an electricity distribution system using (DC) direct current, which lead to many more discoveries into uses of electric energy.
~1885-1890~ George Westinghouse developed an electricity distribution system using (AC) alternating current, which lead to the "War of Currents" with Thomas Edison.
The invention of the light bulb lead to the need for electrical energy distribution. The light bulb could operate on either DC or AC which lead to the "current war". Both technologies have advantages and disadvantages. The debate continues today and with improvements of renewable energy, may one day be settled.
Early period telegraph systems used batteries, limiting its distance and time usage. Because the light bulb created the need for electrical energy generation and distribution, this allowed the telegraph to expand from coast to coast. It is interesting to note that the telegraph used (DC) direct current while the telephone uses both (DC) direct current and (AC) alternating current.
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