How Microwaves Are Made

microwaves

Microwaves are electromagnetic waves with a relatively long wavelength and low frequency. They can be used for communication, radar (Radio Detection and Ranging), masers, circuits, and many other applications.

How They Work

In a microwave oven, an electrical current generates high frequency waves inside the magnetron that travel through a waveguide into a cooking chamber where they reflect off metal walls and stimulate any molecules in the food that respond to this vibrational energy. This is especially effective at heating water-rich foods such as vegetables and meats.

How They Are Made

To produce microwaves, a filament within the magnetron is heated to 3,000 volts. As the filament heats up, it emits negatively charged electrons. These electrons are whipped around in a circular path by the magnetic field created by large magnets above and below it.

When the filament reaches the cathode, or negative terminal, it is energized with a voltage that is magnified to over 3,000 volts. This increases the number of electrons emitted, but the filament is also more sensitive to the magnetic field.

The resulting electric current is amplified to over 3,000 volts, and this voltage is fed to a capacitor that raises the voltage even more. A transformer then feeds the higher voltage to a diode and a small wire called a cathode filament, which is heated up by the 3,000 volts.

The cathode filament combines with the alternating voltage to create a strong electromagnetic field that oscillates at 2.45 gigahertz, which is the maximum frequency of microwaves. The alternating field then causes the electrons to whip past cavities in the anode filament.