Introducing push buttons
A push button is an electronic device that basically acts like a mechanical switch; it can be used for either closing or opening an electrical or electronic circuit. They are also called momentary push buttons, or pushbuttons. Push buttons are made with hard materials such as plastic and have a tiny metal spring inside that makes contact with two wires or contacts, allowing electricity to flow through them if the button is pressed (in normally open push buttons) or when it is depressed (in normally closed push buttons). When the push button is off, the spring retracts, the electrical contact is interrupted, and electrical current will not flow through the contacts. Push buttons are useful for manually controlling or initializing a process in an electrical or electronic circuit, including applications that contain microcontroller boards. The following image shows a normally closed (left) and a normally open (right) push button: