A square wave is a type of waveform that alternates between two levels, typically high and low, with a sharp transition between them. It is characterized by its rectangular shape, where the duration of the high state is equal to the duration of the low state. Square waves are commonly used in electronics and signal processing, as they can represent binary data. Square waves are often generated by electronic circuits, such as oscillators, and are fundamental in various applications, including digital communication and clock signals in microcontrollers. Their distinct on-off pattern makes them useful for testing and controlling devices in a variety of fields.