The Amazing Microwave and How It Works
Step Right This Way! See the Amazing Microwave!
Ah yes, the modern machine of molecular modification, or more commonly, the microwave! Where would popcorn lovers be without this marvelous contraption? In fact, where would hot tea, hot chocolate, leftover meatloaf, or Hot Pocket lovers be without it? Not to mention the crafters out there that use it for non-food related items. The microwave has distinguished itself as an appliance that sees everyday usage. If I have a choice of standing in front of the oven and waiting for my soup to heat up or throwing the bowl in the microwave for two minutes, you bet I'm going to "nuke" it. But what do we mean with the word "nuke"? Is it real nuclear energy at work here? Let's take a look at how the microwave came to be and how it heats up the TV dinners.
Percy Spencer was the first man to make the connection between microwaves and cooking food. While working on magnetrons at the company he worked for, he noticed that the candy bar in his pocket was melting. Through the course of different tests, he began to patent some of the technology. Ironically, the first food tested with microwaves was popcorn! The first microwave oven was built in 1947 by Raytheon, the company where Spencer worked. It was 6 feet tall, weighed in at 750 pounds, cost a walloping $3,000, and was called the Radarange. Needless to say it didn't sell very well. Over the next few decades, other manufacturers took their shot at building the ovens with additional advances, but it wasn't until 1967 when Amana built the first countertop model that it began to find its market. The demand for the microwave grew, and it quickly became one of America's most needed household appliances. Now lets look into the heart of the microwave.
Today's microwaves come in either countertop or above-the-range models. Both are similar, but the above-the-range models have underneath lights and an exhaust fan included. Because of the harmful nature of microwaves to humans and pets, many safety precautions are installed within microwave ovens. They include a number of fuses and two door switches that need to be closed for the appliance to function.
Once the cook timer is set and the start button pressed, electricity gets sent to a relay, more commonly called a triac. The triac activates and sends the electricity to the transformer. The transformer in a microwave takes the regular 120 volt household voltage and increases it to 3000 volts. The dangerous voltage then gets sent to the magnatron tube, where it is converted into microwaves. The microwaves make their way through a wave guide and are then sent into the cooking chamber. A fan blade type of stirrer spins and moves the waves around the chamber. With the waves bouncing around the chamber and your food rotating on the carousel, it makes the most of this efficient cooking option. When any of the switches are opened, the microwave instantly stops.
A common misconception with microwave ovens is that many people believe they cook from the inside out. That's not the case. Have you ever tried heating up a completely frozen gallon of ice cream to make it easier to scoop? It gets all melted and gooey around the edges but the center is still hard as ice. That's because the microwaves penetrate the food all at once, and when a thick item is microwaved, the waves aren't able to penetrate the center as easily. It's also interesting to note that the interior cooking space of the oven does not get hot while microwaving. The food gets hot because the microwaves interact with the molecules in the food, mainly the sugars, fats and water. The molecules absorb the microwaves and turn them into energy. This causes the molecules to bounce off each other and create heat. The actual air in the microwave never gets heated. This process is called dielectric heating.
One negative aspect of dielectric heating is, because the air doesn't get hot, there is no way to brown and crisp food. This was remedied by the invention of those little silver wrap-arounds. They contain small amounts of metal that cause the microwaves to bounce at an extremely high rate within the wrapper, creating heat sufficient enough to brown and crisp.
Now that we've gone over how a microwave oven cooks the food, you may be wondering why yours isn't working very well. Luckily, we have a repair guide to help you make any minor repairs. You'll learn how to diagnose and fix some of the more common problems with microwave ovens. The price on new microwaves has lowered significantly over the last decade, but that doesn't mean you want to buy a new one every time there's a small glitch.
Dave Donovan is a freelance copywriter living in Atco, N.J. An electrician for 15 years, an injury forced him to pursue his true passion - writing.