Having a slice of toast with breakfast is very common around the world. And because of this, most people have a toaster in the kitchen. Although the concept behind this inexpensive appliance is a fairly simple one, the actual mechanics inside a toaster are surprisingly complex.
A toaster is heated by infrared radiation. The essential component of the toaster is nichrome wire, an alloy of nickel and chromium. Nichrome does not conduct electricity well, so when you run electricity through nichrome wire it gets hot.
To view the nichrome wires, look for the coils that turn red. These wires are placed against a mica sheet, and when you plug in a toaster, set the desired amount of toasting and push down the handle, electricity flows into the toaster and through the wires.
Toasters have a knob that allows you to select how dark you want your toast. This knob essentially controls the amount of time that the toast is exposed to the infrared radiation. The longer the toast is exposed, the darker the bread will become.
When the toast is done, it pops out of the toaster and electricity stops flowing. The spring-loaded tray that holds the bread pops the toast up when it is done. When you pull down the handle, you are also setting the spring.
The outer shell of the toaster is usually made with plastic or metal that doesn't touch any of the mechanisms that are inside the shell. The reason for this is to keep the toaster cool to the touch and to not lose any of the electricity drawn into the toaster. While battery-powered toasters do exist, the majority of toasters need to be plugged into an electrical outlet.
Toasters can vary in size and capability, although most household versions can either toast two, four or six pieces of bread at a time. Advanced toasters can have wide slots to hold bagels and variable settings that include defrosting capabilities. Some companies make food items that are specifically designed for the toaster, such as Pop Tarts.