Kind of like a lot of modern big inventions also microwave was minor product of different research. In this case it was about magnetron, it was microwave source of British radar from the Second World War. It was researched with the team of scientists (John Randall and dr. H. A. H. Boo from Birminghham university) in year 1940. The magnetron can make electromagnetic waves with a average length 12 cm about frequency 2450 MHz (it is approximately the high part of the frequency, by which satellite signal comes to us from converter to cable into satellite receiver).

Percy Spencer
(picture from web page http://members.aol.com/spencerlab/history/readdig.htm)

Sometime around the year 1946 dr. Perci Spencer – original farmer boy, later “engineer self – taught person “ – he is interested by research connected with radar. Through it he noticed something unusual: The pastry melted in his pocket. It made Spencer to next experience. He put corn near magnetron and he observed it by the enthusiastic way of the scientist, as this one broke and burst and shot over whole laboratory. Next morning he put an egg near magnetron and together with colleague watched how the egg was shivering and trimming. The egg become be quickly hot and there was created excess pressure. Spencer colleague turned down to this egg to can watch the whole event better, when the egg broke and the hot contain got on his frightened face. But Spencer face becomes sparkled because of the conclusion: The hot pastry, broken corn so exploded egg were in consequence of microwave energy. What about to warm this way some other food?

Spencer finished a metal case that could be closed and he put into it microwave source. When he put some meal in it and switched source, the meal was hot soon, apart from other things because energy could got out. A new revolutionary cooking and multimillionaire dollars industry were on the world.

It was necessary to finish Spencer idea into a practice using in next development. In the end of 1946 Raytheon Company finished peten proposition and the first microwave was produced. It was tested in one from Boston restorations. One year later the fist microwaves were in the trade fair: high 165 cm, weight . . . kg, price 5000 $. Much more it was necessary to cool the magnetron with water, so you had this oven imbued to duct.

The first commercial microwave
(picture from web page http://www.gallawa.com/microtech/history.html)

The first swallow didn’t sell well however. Only, when the new, lighter and cheaper ones came with a new magnetron, that was cool by air, the demand started increase. Especially in restorations and self – services, they could have stored frozen meat and then they could warm it about order. But it was not only food industry that learned advantage of this new equipment. So the different kind of industry started to use microwaves to dry cork, ceramic paper, lather, textiles and so on. It seems to mass production nothing is in a way. But there became some myths. There started some afraid from this ray on the human body. There started to tell about blind, sterility and so on. But not long time. After 1975 the selling started increase again, in 1976 microwaves were in 60 % of American home holds. On the old Continent they started to sell after 1980, when people realised that they could warm their pre – cooked meal fast and cheaply. In present day the preparing meal in microwaves is known on the whole world and it become international phenomena.

Microwave ETA 199
(picture from web page http://www.eta.cz/karty/mikrovlny.html)