Microwave Oven Working Principle

Some of the best descriptions of this proverb are the enduring technologies that took birth during the Second World War. A byproduct of one such ground-breaking technological advancement that helped to alter the course of the war in the 1920s and 1930s is the well-known microwave oven. The magnetron tubes, which were initially used in the development of long-range military radar, gained their commercial application after World War II.

Although the scientific community was familiar with the heating characteristics of radio waves since the 1920s, it was not until 1945 that Percy Spencer, a self-taught American engineer, accidentally discovered the thermal effect of a high powered microwave beam. In 1945, Percy noticed that a peanut bar he was carrying in his pocket began to melt as he was standing next to a working magnetron tube. (Read More: Do Microwave Ovens Kill Bacteria or Germs in Food?)

Spencer, working for the Raytheon corporation, filed a patent application for a microwave oven on October 8th, 1945. In 1947, Raytheon launched the first commercially available microwave oven by the name “Radarange.” Since then, the microwave oven has undergone a number of improvements and has been utilized in a number of culinary processes, from roasting to instant reheating. But how is it possible for something we use for communication to also cook our food? Well, let’s try to understand this by exploring the science behind it.

Microwave Oven Working Principle

Working Principle of Microwave Oven

The idea behind how microwave ovens work is the transformation of electromagnetic energy into thermal energy. Electrical and magnetic fields that oscillate perpendicular to one another are referred to as electromagnetic (EM) energy. When a polar substance, i.e., a molecule containing opposite charges, falls in the path of these It oscillates to match electromagnetic radiations. Because of the friction and collisions between molecules, the dipole loses energy and heats up as a result.

Also Read: How Long Do Microwave Ovens Last – Signs That It It Going Bad

When the water molecules in our food products come into contact with microwave radiation, a similar phenomenon occurs, heating the food from the inside out. Microwaves are electromagnetic radiations with frequencies ranging from 300MHz (0.3 GHz) to 300 GHz and wavelengths that range from 0.9 meters to.0009 meters, respectively. In most of thhttps://www.homeservicesoffers.com/why-does-microwave-not-heating/e ovens, the microwave used is of 2.24GHz frequency (i.e., wavelength = 12.2cm). Due to the nonpolar nature of air, these dimensions allow microwaves to reach deep inside food and cook it there while maintaining a constant temperature in the surrounding air.

A widespread misconception holds that water resonances are naturally induced by microwaves in microwave ovens. The frequency of a microwave oven is much lower than any naturally occurring resonance in an isolated water molecule, and in liquid water, those resonances are so muddled that they are hardly audible anyway.

Microwave Oven Working Principle

Main Components of Microwave Oven

High Voltage Transformer: The microwave oven needs more power than the typical voltage that the house’s electrical wiring can supply, unlike many other household appliances. A step-up transformer with a high-voltage output is installed inside the oven to achieve this. The 240V supply is raised to a few thousand volts and then fed to the cavity magnetron.

Cavity Magnetron: A cavity magnetron is a powerful vacuum tube that converts electrical energy into long-range microwave radiations, making it the most crucial part of a microwave oven.

Micro-controller: A microcontroller is something that enables communication between a user and a machine. One or more processing cores, memory, and programmable input/output peripherals are all part of the controlling unit. It processes the instructions that a user gives to the microwave oven and also displays them on a seven-segment display or a LED screen, depending on the model of the oven.

WaveGuide: In keeping with its name, a waveguide is a hollow metallic tube that directs waves produced at the magnetron’s output toward the cavity, which is where we put the food.

Cooling Fan: The magnetron’s efficiency and longevity are ensured by cooling fans, which lower the device’s operating temperature.

Microwave Oven Working Principle

Working Mechanism

The process of heating food in the microwave oven is fairly simple; however, the mechanism involved in that process is somewhat atypical. The waveguide directs the microwaves after they are generated at the magnetron in the direction of the food in the cavity. The food’s water molecules are exposed to the microwaves as they pass through the surface and enter the food. The polar molecules of water try to follow the electric field as it shifts over time by shifting their orientation inside the material to align with the field lines in an energetically advantageous configuration (specifically, with the positive side pointing in the same direction as the field lines). The material’s temperature rises as a result of these molecules’ rapid direction changes (at least millions per second). Dielectric heating is the term for this procedure. Because microwave energy decreases according to the inverse square law, the cavity chamber in which we place food is created to maximize the heating effect of microwaves. Additionally, the majority of microwave ovens have a door switch that prevents the process from starting until the door is completely shut.

Microwave Oven Working Principle

Precautions While Using Microwave Oven

  • It is crucial to abide by the manufacturer’s instructions manual for your oven model when it comes to suggested operating practices and safety precautions, just like with many other electrical appliances.

  • Use cooking utensils made specifically for use in microwaves.

  • You shouldn’t use a microwave with a door that is open, crooked, or damaged.

  • It is advised not to stand directly in front of a microwave oven while it is running to prevent any accidents.

  • The liquids should not be heated longer than the recommended temperature as it can cause the water vapors to reach the electric components and interfere with their working.

  • The cavity must be routinely cleaned with water and a mild detergent. Scouring pads, steel wool, and other abrasives are advised against being used during the cleaning process.

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