It isn't magic that pops your popcorn or reheats your lukewarm coffee. It's high-frequency electromagnetic radiation. Microwave ovens generate this radiation in the form of microwaves, using this process:
1. A transformer boosts the normal household current — 120 volts AC — to about 4,000 volts DC.
2. The transformer supplies this beefed-up energy to an electronic tube called a magnetron, which in turn converts the energy into microwaves.
3. The microwave energy travels along a metal conduit called a wave guide, into the interior metal cooking chamber of your microwave oven.
4. A fan-like device called a stirrer, located at the top of the oven, disperses the microwaves evenly as they leave the wave guide.
5. The metal interior of the cooking chamber reflects the microwaves (they can't penetrate metal), agitating the water molecules in the food or liquid inside. The resulting friction generates heat, which quickly cooks or heats that frozen entree or coffee.
6. A fan sucks up the heat from the cooking chamber and cools the magnetron.
Safety and Use
Because microwave ovens produce radiation that can harm you if you are directly exposed to it, today's ovens must meet strict safety standards and are designed to prevent significant leakage of microwave energy. For example, a tight door seal and a metal screen over the glass window on the oven door prevent harmful energy from escaping; a system of locks keeps the oven from operating if the door latch is open.
But just to be safe, take these additional measures to protect yourself and your oven.
- Call in the professionals. A broken or damaged microwave oven is more than an inconvenience — it's a potential hazard. If you have problems with your oven, call a service technician. By design, the ovens are difficult for a layperson to disassemble, and you may render the oven unsafe (voiding your warranty) if you tamper with it yourself.
- Follow instructions. Follow the owner's manual for recommended operating procedures and safety precautions for your model.
- Don't overheat. Don't excessively heat food or liquids, especially in sealed containers; if not properly ventilated, they can burn you or explode. Periodically stir or turn items to avoid hot spots that uneven cooking can create.
- Don't run an empty microwave. You could ruin the magnetron.
- Don't use metal. Don't use metal items or foil in your microwave, unless intended for that purpose. Metal reflects microwave energy and can create a magnetic charge that can damage the magnetron or disperse the energy into the air. Use only microwave-safe products (usually indicated on the packaging or the product itself).
- Watch your door. Keep door seals clean. Never operate a microwave oven when the door is broken, warped, bent or won't close tightly, or if there's any chance the oven will continue to run with the door open.
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