What is a Magnetron?

science engineering

Typically used in microwave ovens, a magnetron is a tube that utilizes electrical and magnetic currents in order to create an intense heat output. The electromagnetic energy created from a magnetron can travel at the speed of light and is the same type of energy used in radio and television broadcasting. A magnetron tube has a filament in the center which heats up when it is exposed to a slight amount of voltage or energy. The filament gives off electrons as it becomes hotter. These electrons move outward in search of positive anodes, or electrodes, but they come in contact with a negative magnetic field along the way.

The negative magnetic field within the magnetron repels the electrons. As a result, they become stuck in one area and begin rotating in circles. This creates more heat, as well as a supply of energy strong and hot enough to quickly cook an item.

In the 1920s, a General Electric employee, Albert Hull, was researching vacuum tubes when he created the magnetron. However, Hull could think of few uses for his invention, and the magnetron remained largely unused for another ten years. In the late 1930s and early 1940s, two engineers named Harry Boot and John Randall decided to explore the magnetron further. Instead of using glass to create the outer casing of the magnetron, they used heat resistant copper to create a magnetron capable of incredible microwave output. Their creation allowed for an output of 400 watts in a space smaller than four inches (10 cm).

As Boot and Randall developed stronger magnetron tubes, they discovered the tubes were ideal for sonar waves. During World War II, United States submarines began utilizing these tubes, which allowed the sonar equipment to help them detect enemy ships more quickly. In the late 1940s, Dr. Percy Spenser, who worked for Raytheon Corporation, further tested the output of magnetron tubes in his lab. He noted that the candy bar in his pocket had completely melted while working with the tubes. He decided to place a few kernels of popcorn near the machinery to see what would happen, and noticed it made the kernels pop.

Dr. Spenser called for his assistant and the two men decided to place a whole egg near the magnetron tube. When the egg exploded, Dr. Spenser realized he had discovered a fascinating form of cooking. Dr. Spenser went on to help create the world's first microwave oven in 1947. The first model weighed over 700 pounds (318 kg), was more than five feet (1.5 meters) tall, and cost more than 5,000 US dollars (USD).

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New: Discuss this Article

Posted by: anon13459
How is magnetron important to the human aspect?
Posted by: anon6886
I been using microwaves since a loooong time now, my baby tells me today that it is correct to turn off the power knob first and then open the door. I believe when you do open the door while the micrrowave is working its shuts the power off as a safety feature. so I am curious, is it "ok" to open it while it is operating?? I have been doing it for ages now.....kindly help !!!!

Posted by: timdives
Is a magnetron radar capable of detecting underwater explosives? if not what would be the tool to use without blowing up?
Posted by: anon4658
You don't mean SONAR. You mean RADAR. The magnetron is a microwave device.
Posted by: FireBird
Unlikely, since the interior of the oven is designed not to be adversely affected by the frequencies produced by the magnetron. More likely is that steam has degraded it, or possibly it could suffer damage if the oven was turned on with nothing in it to absorb the energy.
Posted by: anon1454
could a faulty magnetron in a microwave cause the interior of the oven to scorch?

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