A musical keyboard is the set of adjacent depressible levers or keys on a musical instrument. Keyboards typically contain keys for playing the twelve notes of the Western musical scale, with a combination of larger, longer keys and smaller, shorter keys that repeats at the interval of an octave. Depressing a key on the keyboard causes the instrument to produce sounds, either by mechanically striking a string or tine ( piano, electric piano, clavichord), plucking a string ( harpsichord ), causing air to flow through a pipe (organ), striking a bell (carillon), or, on electric and electronic keyboards, completing a circuit (Hammond organ, digitalpiano, synthesizer ). Since the most commonly encountered keyboardinstrument is the piano, the keyboardlayout is often referred to as the " pianokeyboard".
