When was the first microwave oven invented?

Dr. Percy Spencer invented microwave oven in 1946 while testing magnetron for radar system. Spencer was working with Raytheon Corporation on his project when he discovered that a sweet candy placed in his pocket melted due to rapid temperature rise. The other day he tried and tested the same with popcorns and then with an egg, he was surprised to find cooked corns and egg in his lab. He shared his experience with his colleagues and started working on his new invention.

This first commercially produced microwave oven was about 6 feet tall and weighed around 750 pounds.