It's strange that in such recent history, so many basic facts don't seem to be certain. Percy Spencer may have been 18 months old or 3 years old when his father died and his mother abandoned him to his aunt and uncle. No matter; he never graduated from grammar school but started working when he was twelve years old at a spool mill. At age 16, he helped install an electrical system in a local paper mill. Since such systems were new, no one knew much about them, so through trial and error, he and three others made it work.
Some would say that his early circumstances put at a distinct disadvantage in a capitalist economy. Capitalism isn't restrained by circumstances or levels of education and Percy Spencer is a very good example of that.
As soon as he turned eighteen, he joined the U.S.Navy to learn wireless telegraphy. Some time in the 1920s, he went to work for Raytheon, from which came radio vacuum tubes and rectifier tubes that allowed radios to run from house current instead of batteries.
Raytheon received a contract to build devices made to create magnetrons for radar systems to be used in World War 11. Spencer soon found a way to mass produce magnetrons, increasing the output from about 17 each day to over two thousand.
The discovery of the microwave oven was an accidental outcome of this process. It's said that as Percy stood near an operating magnetron, a chocolate bar in his pocket melted. After a few experiments, one in which an egg exploded in his face, he developed the idea that food could be cooked by these microwaves and Raytheon put a team of engineers to work to build an appliance to contain them.
The first microwave oven was a huge affair, at 66 inches tall and 750 pounds. Costing $5000, it was used to cook food in a Boston restaurant. Since it had to be cooled, like nuclear reactors do today, it had to be plumbed into the building so installation was expensive, too. It was not popular because of these limitations, but with improvements, the oven caught on.
The microwave oven was not the only invention of Percy Spencer. He held from 150 to 300 patents over his lifetime.
He became the Senior Vice President of Raytheon and a member of the Board of Directors. He was also a Fellow of the American Academy of Arts and Sciences and was awarded honorary Doctor of Science degree from the University of Massachusetts.
For an orphan with no education, that's not bad.