The holes on the inside of microwave oven doors serve a crucial safety purpose. They are actually a part of the microwave's design to prevent microwave radiation from leaking out of the oven while it is in operation. These holes are commonly known as "waveguide covers" or "ventilation holes."
Here's how they work:
Microwave radiation containment: Microwaves generate electromagnetic radiation at a frequency of approximately 2.45 GHz. This radiation is used to cook food by exciting water molecules and generating heat. However, if this radiation were to leak outside the microwave cooking chamber, it could be harmful to people and pets nearby. The waveguide covers help contain and direct the microwave radiation within the cooking chamber, preventing it from escaping through the door and other openings.
Ventilation: The microwave oven's cooking process can produce steam and condensation inside the cooking chamber. The ventilation holes on the waveguide covers allow for the release of excess moisture and prevent the buildup of steam, helping to keep the interior of the microwave clean and dry.
Cooling: The magnetron, which generates the microwaves, can get quite hot during operation. The ventilation holes also help dissipate some of the heat and ensure the proper functioning and longevity of the magnetron and other internal components.
It's crucial to maintain the integrity of the waveguide covers and keep them clean to ensure that the microwave operates safely and efficiently. Damaged or dirty waveguide covers can lead to microwave radiation leakage, reducing the effectiveness of cooking and posing a potential safety hazard. If you notice any damage or issues with the waveguide covers, it's essential to have the microwave inspected and repaired by a qualified technician.