Hoffman Amplifiers Tube Amplifier Forum
Other Stuff => Other Topics => Topic started by: Ritchie200 on August 24, 2018, 03:24:02 pm
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Interesting short history of year and event of electrical firsts. It gets crowded in the late 1800's when the information was still fresh in the writers of the day. If you are having trouble sleeping.....
Jim
https://www.mikeholt.com/files/PDF/History%201%20-%20chronologicalhis00natirich.pdf
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I liked these developments....
"1927 The pentode tube for radio is developed, making possible unlimited audio-frequency amplification without distortion."
"1931 The "alnico" permanent magnets are discovered by a Japanese named Mishima in March. He files applications in Japan covering his discoveries and later obtains corresponding patents in the United States January 14, 1936. These patents are numbered from 2,027,994 to 2,028,000 inclusive. The "alnico" permanent magnets are the strongest ever produced."
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I didn't see anything on the Egyptians and their pyramids :icon_biggrin:
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Georgio has that covered on the History channel. :icon_biggrin:
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That pentode quote is a mis-translation. A *triode's* gain between two tuned radio circuits is very limited by reverse transfer capacitance. Pentode (or tetrode) solves that. In audio, a pentode *power* tube is more efficient and became easier to drive, thus cheaper overall. Oh, and it can give large gain at low signal levels but that is rarely vital.
I never knew Alnico was discovered/invented by a Japanese. Alnico WAS the very best magnet for a very long time, and underlay many loudspeaker developments; also "won the war" as the magnet in radar magnetrons. Ceramic became much cheaper, Neo is much smaller and has eaten much of Alnico's lunch, but it is still around.
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Great stuff. So far just took a quick look. I love the history of science. I think some interesting points do not make their way in to the outline format of this piece. This has prompted me to some musings.
We eat, live and breathe by Ohm's Law: that given current flow, voltage drops across a resistance. But when published, Ohm's work was so controversial and poorly received that he resigned an important post in Cologne. If I remember right, the ideas of Peter Barlow then held sway: that voltage was a constant. With the increased use of telegraphy it eventually became evident that Ohm was right - voltage did drop across the resistance of long runs of wire.
Outside the realm of electricity, telegraphy grew in tandem with the railroads. This caused the need to unify clocks and the concept of time across immense distances, which in turn lead to the development of relativity theory by Einstein. Separately, it lead to the development of modern weather theory with large patterns of similar weather divided by fronts. Weather on either side of a front line is very different, which previously fooled people into surmising that weather was purely local. They had no way to know about the larger weather patterns until there was widespread use of the telegraph.
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this poor guy was missed in the index;
https://en.wikipedia.org/wiki/Heike_Kamerlingh_Onnes
It amazes me how the human mind "gets there from here"
It also hurt my brain when my instructors started doing math to explain things instead of just dumping the liquid helium and watching :icon_biggrin: