Brief microwave oven history. Dr. Percy Spencer of the Raytheon Corp. invented the microwave oven, the first discovery made on a research project around 1946. Includes link to six part microwave technology series.

A Dr. Percy Spencer, a self-taught engineer with the Raytheon Corporation, invented the microwave oven. He first noticed something very unusual during a radar-related research project around 1946. He was testing a new vacuum tube called a magnetron when he discovered that a chocolate bar in his pocket had melted. This interested Dr. Spencer, leading to another experiment where this time he placed some popcorn kernels near the tube and watched as the kernels exploded.

He concluded that the melted chocolate bar and the cooked popcorn were all attributable to exposure to low-density microwave energy. He continued to experiment with other foods on the basis that if these foods can be cooked that quickly, why not other foods?

He later created a metal box with an opening, which he fed microwave power. The energy entering the box was unable to escape creating a higher density electromagnetic field. When food was placed in the box and microwave energy fed in, the temperature of the food rose rapidly. Dr. Spencer had now invented what was to become the microwave oven.

The first ovens were called 'Radaranges'. The first commercial applications and patents were based in the U.S.A. but there were parallel developments in Britain and Europe. Before long, microwave ovens became a commonly owned kitchen appliance.