The Inventi on of

the Microwave!

Percy Spencer, the inventor of the first microwave oven, perceived his idea after World War II from radar technology developed during the war. Named the Radarange, it was first sold in 1947. Raytheon later licensed its patents for a home-use microwave oven that was first introduced by Tappan in 1955, but these units were still too large and expensive for general home use. The countertop microwave oven was first introduced in 1967 by the Amana Corporation, which was acquired in 1965 by Raytheon.

I can finally cook food

without the hassle!

Spencer was born in Howland, Maine. At the age of just 18 months old, Spencer’s father died and his mother soon left him to his aunt and uncle. His uncle then died when Spencer was just seven years old. Spencer subsequently left grammar school to earn money to support him and his aunt. At the age of 12, he began working from sunup to sundown at a spool mill, which he continued to do until he was 16 years old.

At this time, he heard of a local paper mill that was going to begin using electricity. Spencer was from a very remote community in Maine, where people knew very little about electricity. He was so intrigued that he began learning all he could. He applied for this work at the paper mill, and was one of three people who were hired to install electricity in the plant, despite having never received any formal training in electrical engineering nor even finishing grammar school.

Electricity is the future! I need to know about the future to progress!

By 1939 Spencer became one of the world’s leading experts in radar tube design. Spencer was now working at Raytheon, a contractor for the United States Department of Defense, as the chief of the power tube division. Largely due to his reputation and expertise, Spencer managed to help Raytheon win a government contract to develop and produce combat radar equipment for M.I.T.’s Radiation Laboratory. This was of huge importance to the Allies and became the military’s second highest priority project during WWII, behind the Manhattan Project.

I’ll design radio tubes for you! I might even come up with a few ideas!Alright! We need radio equipment for our soldiers!

At that time, magnetrons were used to generate the microwave radio signals that are the core mechanism of radar, and they were being made at the rate of 17 per day at Raytheon. Spencer developed a more efficient way to manufacture them, by punching out and soldering together magnetron parts, rather than using machined parts. His improvements were among those that increased magnetron production to 2,600 per day. For his work he was awarded the Distinguished Public Service Award by the U.S. Navy.

Wouldn’t it be easier to make them like this?It sure is!

Excellent work! Here’s this for your efforts!

One day while building magnetrons, Spencer was standing in front of an active radar set when he noticed the candy bar he had in his pocket had melted. Spencer was not the first to notice this issue, but he was the first to investigate it. He decided to experiment using food, including popcorn kernels, which became the world’s first microwaved popcorn. In another experiment, an egg was placed in a tea kettle, and the magnetron was placed directly above it. The result was the egg exploding in the face of one of his co-workers, who was looking in the kettle to observe.

We should do more testing!

Look! My candy bar is melting on that radar machine!

Spencer then created the first true microwave oven by attaching a high density electromagnetic field generator to an enclosed metal box. The magnetron emitted microwaves into the metal box blocking any escape, allowing for controlled and safe experimentation. He then placed various food items in the box, while observing effects and monitoring temperatures.

Look what I made! It’s a high density electromagnetic field generator!

It’s a true microwave oven!

Raytheon filed a patent on October 8, 1945 for a microwave cooking oven, eventually named the Radarange. In 1947 the first commercially produced microwave oven was about 6 feet tall, weighed about 750 lbs., and cost between $2,000 and $3,000. In 1967 the first relatively affordable ($495) and reasonably sized (counter-top) microwave oven was available for sale.

Thank you

Raytheon! It’s

so much easier

to cook now!

The microwave oven today is now a simple household item used commonly in homes across the world. Microwave ovens now, unlike the 1900s, come in varying sizes, shapes, textures, intensities, and styles. There are dozens of companies that produce microwave ovens daily; but they all respect the true inventor, Percy Spencer.

THE END