I like to know how things work.  Sometimes I can figure things out by observation, but other times I want someone to explain the details to me.  Toasters and toaster ovens are pretty straightforward  appliances, but for those of us who want a bit more information, howstuffworks.com offers this:

How Toasters Work

Most electric pop-up toasters all operate in the same manner. A slice of bread, a frozen waffle, a toaster strudel, or some similar food item is placed through a slot in the top of the toaster and into the carriage. The carriage is lowered into the chassis using the lever at the side of the toaster.

When it reaches the bottom, the carriage latches in position and an internal switch is activated to start the heating process. A thermostat determines how long electric current will be sent from the power cord to the heating elements.

The person who is operating the toaster sets the thermostat using a control knob or lever calibrated between light and dark. When the desired temperature is reached and the heating process is completed, the solenoid turns the current off, then unlocks the latch and allows the carriage to spring up to its original position. At this time, the toasted food is easily reachable and can be removed by the operator of the appliance.

©2006 Publications International, Ltd. This cross section of a toaster indicates the various elements that make a toaster work.

How Toaster Ovens Work

To operate a toaster oven, controls are set, the door is opened, food is placed on a tray, and the door is closed. If set for toasting, a toaster thermostat operates the upper and lower heating elements as selected by the color controller. If set for baking or broiling, the baking thermostat operates the heating elements as selected by the temperature controller and possibly by a timing mechanism.

©2006 Publications International, Ltd. The cross section of a toaster oven.

So there it is, simple, yet indispensable in our kitchens.