How Does a Microwave Work? Understanding Microwave Mechanics

From reheating leftovers to preparing recipes incredibly fast, microwaves have become indispensable in kitchens worldwide. Unlike traditional ovens, microwaves heat food with a unique technology that saves both time and effort, giving you more time to spend with your family while dinner is cooked to perfection. Modern microwaves have cooking modes or settings similar to traditional ovens, like baking, broiling, convection, etc., to help you pull off any recipe easily. Microwaves are available in different models like countertop models, built-in models, and over-the-range microwaves, but their functions are almost similar. By knowing how your microwave works, you can maximize its use, making cooking even easier.   

In this article, we’ll cover: 

  • What are the different parts of a microwave? 
  • How do microwaves cook food? 
  • FAQs about how microwaves work  

What Are the Different Parts of a Microwave? 

A microwave comprises several parts, but 9 are considered major components. These 9 parts are responsible for the microwave's overall functioning; if one fails, the microwave's heating capacity will be affected. The 9 major components include internal and external parts, each of which has a separate role to play in streamlining that perfectly cooked meal.  

Check out the list below to learn about the major components of a microwave and their functions:  

  • Power chord: This is a necessary component in all models and makes of microwave ovens. The power chord helps connect the appliance to the power source. Most modern microwaves need a grounded 3-prong outlet with an electrical supply range of 120 volts and 15 or 20-amp.  
  • Control panel: This external component allows the user to preset the cooking time and modes like defrosting, quick heating, broiling, baking, etc. The control panel lies beside the door of the microwave and comes with a set of buttons that enable the controls.  
  • Magnetron: The microwave gets its name from the magnetron placed inside it. The magnetron produces electromagnetic waves that heat the food. These electromagnetic waves bounce off the walls, flow through the turntable, and reach the food. They create friction between the molecules in the food to produce heat, resulting in its cooking.  
  • Voltage transformer: Modern microwaves need 3,000 to 4,000 volts to work properly. This requirement falls short as most electrical sources provide only 120 volts of electricity. The voltage transformer plays a crucial role here. It transforms the electricity into a higher voltage to meet the microwave’s requirements and speeds up the cooking or heating process.  
  • Turntable: The round plate at the bottom of the microwave is called the turntable. It rotates to ensure your food cooks evenly. It is important to place the turntable properly before using the microwave for heating or cooking meals.  
  • Cooling fan: As the name suggests, this fan is used to keep the microwave cool or prevent overheating. The fan automatically turns on when the microwave starts operating. It frequently turns on and off to regulate the temperature inside. The fan is attached to a separate vent that releases moisture and odor from the cooking cavity. 
  • Waveguide/cover: This is a metal tube or plate that transfers or directs the microwaves produced by the magnetron. The wave transports the microwaves from the magnetron to the cooking cavity to ensure faster cooking. The fan turns on and off when the cooktop at the bottom is used to maintain the temperature inside. It is also attached to a separate vent through which the fan removes moisture and odor from the microwave’s cooking chamber.    
  • Cooking cavity: This is the compartment or chamber inside the microwave where the food is placed for cooking or heating. The power produced by the magnetron is transferred to this cooking cavity, where it heats the food and aids in cooking. The microwave cavity should be cleaned after each use to ensure the food is cooked hygienically every time. This will also prevent the food from absorbing the smell of other food cooked before it.  
  • Door: This is an external component that not only blocks the microwaves inside the cooking cavity but also allows the user to view the food while it is being cooked. The food can be seen while the turntable rotates to ensure your food is cooked well. Opening the door before the cooking ends will immediately stop the cooking cycle and automatically reset the pre-set cooking time and cooking mode. 

How Do Microwaves Cook Food? 

In essence, a microwave cooks and heats food using electromagnetic energy. However, that only sums up the basics of the cooking method because this master cooking appliance has more to it. From the functions of the components discussed above, you already have an idea of how the microwave generates the waves that aid cooking. Now we will delve deeper into the process and also decode the principle behind every cooking mode.  

The rays or microwaves generated by the magnetron hit the walls of the cooking cavity and reflect to reach the food. The food's water, sugar, and fat content then absorb these microwaves. Soon, these rays start exciting the molecules inside the food by generating friction, producing heat. This heat cooks the food. Because of this principle, the food cooks inside-out in the microwave, unlike traditional ovens where the food is cooked outside-in. It also explains why only the food inside the microwave becomes hot, not the air around it. The heat of the microwave changes depending on the cooking mode or cycle. Modern microwaves, irrespective of their model and make, have a few settings like convection, sensor setting, top-down heat cycle, and low-heat cycle.  

The convection cooking mode is similar to baking in a traditional convection oven. The air inside the oven is heated, and the fan circulates the heat evenly for uniform cooking. A microwave generally uses around 1,500 watts of power in this setting to heat the food inside out while sealing in its moisture and flavor. Some microwaves may have a dual convection setting that alternates between modern convection and inside-out cooking and a traditional oven of outside-in cooking. 

Sensor cooking mode heats the food according to the requirement of the cooking mode that has been preset on the control panel. The sensor inside the microwave senses the heat and moisture level of the food while it is being cooked and adjusts the heat accordingly to give perfect results. Some microwaves have a top-down heat setting, also called broiling. It is used to make the food crisp or for browning, just like a traditional oven. During the top-down heat setting, the microwave produces heat directly from the top that flows down to the bottom, adding extra crunch to the food. 

The low-heat setting is likely the most used cooking cycle in every kitchen because it is generally used for quick defrosting or heating food. It is also a good setting to keep food warmer for longer without sacrificing its quality. During this cycle, the magnetron produces enough heat to keep the food warm for up to 6 minutes, so the food can be ready to be served at once. 

FAQs About How Microwaves Work 

How does the technology work in a microwave? 

A microwave oven has a magnetron that acts as the heating element in the appliance. The magnetron generates electromagnetic energy or microwaves when the appliance is switched on. These waves then travel to the cooking cavity and bounce off the walls to hit the food. As the food absorbs these waves, the molecules in the food are stimulated to produce heat, which starts the cooking process. 

The heat generated for cooking is monitored by a sensor that controls the magnetron. Once the temperature in the food reaches the desired range set on the control panel, the magnetron stops generating microwaves. As the temperature in the food drops below the preset range, the magnetron resumes working. This is also why a microwave oven cooks the food from the inside first and then on the outside. 

Does a microwave cook from the inside out? 

Yes, a microwave starts heating the food from the inside, and the heat is gradually transferred to the outside. The microwaves or electromagnetic rays produced by the magnetron are transported to the cooking cavity through a waveguide. These waves reflect from the walls of the cooking chamber to flow through the food. The sugar, water, and fat content in the food absorb these waves, and the food starts heating up. The heat is generated from the friction between the food molecules soon after the microwaves hit them.  

As the food inside the microwave is cooked inside out, the temperature around the microwave doesn't rise as much as that of the food. You will only notice the food getting hotter, not the air around it.  

Which is better: microwave or oven? 

A microwave cooks food faster than traditional ovens and doesn't require much human intervention. You can preset the cooking mode and time to enjoy time with family and friends while dinner is cooked to perfection. With a traditional oven, you have to invest the time to make dinner in the kitchen instead of spending it doing something you love. 

Unlike traditional ovens, microwaves don't require preheating before cooking as it functions at full capacity right from the moment it is switched on. Modern microwaves are available in different models with various cooking modes like convection, broiling, baking, etc., similar to a regular oven. 

Is microwave radiation harmful to humans? 

Microwave radiation can heat the human body the same way it heats food. This can lead to severe burns if the user is not careful. The electromagnetic radiation from a microwave is harmful to the eyes and testes of humans as blood flow to these parts is less than to other parts of the body. As a result, the heat is not carried away through the bloodstream as fast as it is in other parts of the body. 

Final Thoughts 

A microwave can transform your cooking experience, saving you loads of time and effort in the kitchen. Modern microwaves are loaded with features that can easily replace traditional ovens for good. If you want to upgrade from a regular oven to a microwave or add this wonder appliance to your kitchen, then Coast Appliances is the place to look for the model that suits your requirements and budget. You will find all models of microwaves, such as built-in, over-the-range, countertops, and more, from top brands on our website. To answer any further queries, check our microwave buying guide to know which type of microwave will complement your kitchen.