Inside an Electric Toaster

For generations, the simple toaster has warmed and browned everything from bread to waffles. This toaster isn't as simple as it may seem, though. It uses electronic components like capacitors, microchips and even an electromagnet.

To make toast, the first step is placing the bread in one of the trays on the toaster.

This is an internal view of the bread trays.

Once the bread is in place, the next step is pressing the lever. The lever, shown here in red, connects to a metal plate.

A wedge is attached to the metal plate. Go to the next image to see why the wedge is important.

The wedge forces strips of metal to touch contacts on a printed circuit board (PCB).

The strips of metal touch the contacts, completing a circuit. This causes electricity to flow through nichrome wires wrapped around mica plates.

The wires heat up due to electrical resistance. They warm the plates, and the plates toast your bread.

Also, attached to the metal plate is a metal bar, a spring and the trays that hold the bread. The metal bar touches an electromagnet. This electromagnet holds the bar, the trays and the lever in the down position until the circuit breaks. Then, the magnet lets go, and the spring pulls the plate to the up position.

A second printed circuit board controls how long it takes for the electromagnet circuit to break. It uses wires, resistors and microchips to send instructions from the toaster's controls to the electronics inside.

When you push a button, it presses a switch on the printed circuit board. A light-emitting diode (LED) next to the button lights up, and the printed circuit board changes how current flows through the toaster.

You can also turn a dial connected to the variable resistor to adjust the darkness of your toast. The resistor affects how quickly current travels to a capacitor. The more resistance the current encounters, the darker your toast will be.

Some toasters come with several plates that allow you to toast designs into the bread. Instead of moving from the mica plates straight to the bread, the heat moves from the mica plates to the decorative plates, which direct the heat only to parts of the bread. For more information, see How Toasters Work.