A toaster is a small kitchen appliance that browns bread to make toast. It is small enough to fit on the countertop and comes in a 2-slice model or a 4-slice model. It has different settings for toasting slices of bread so that you can have very lightly toasted, dark or somewhere in between. Usually there are 6 settings you can choose by turning a knob at the bottom. On the four-slice variety, you can choose a setting for each section, so that you can have two slices toasted lightly and the other two slices somewhat darker. Some models have a defrost mode for times when you have frozen bread and forget to take it out of the freezer.
Toasters are not expensive appliances and you will find one in virtually every home. In spite of the fact that they the most used appliances, they are very sturdy and a toaster will last for years. They work on the principle of infrared radiation. When you put two slices of bread in a toaster and push down on the lever to bring the bread down into the appliance, the coils on each side of the slice light up. These coils then char the surface of the bread.
Nichrome wire wrapped back and forth across a mica sheet helps create the infrared radiation. This wire is an alloy of nickel and chromium and has features that make it excellent for this use. First, it has a fairly high electrical resistance and secondly, heating does not cause any oxidization. The slots in the toaster are large enough to accommodate a slice of bread. Each lever has a spring-loaded mechanism that pops the bread out when it is browned to the consistency of the chosen setting. It does this because of the timer that automatically turns the toaster off and in so doing causes the tray to pop.