Mechanical or electronic device that produces a back-and-forth periodic motion .
A pendulum is a simple mechanical oscillator that swings with a constant amplitude, requiring the addition of energy at each swing only to compensate for the energy lost because of air resistance or friction. In electronic oscillators, electrons oscillate with a constant period and also require the addition of energy to replace energy loss. Electronic oscillators are used to generate alternating current and high-frequency currents for carrier waves in radio broadcasting. They are incorporated in a wide variety of electronic equipment.