• The signal, such as a voltage or current, that causes the function of a component, circuit, device, piece of equipment, system, process, or mechanism. Also called excitation signal, or drive (1).
  • The action of providing excitation (1). Examples include the application of signal power to a transmitting antenna, a voltage to an oscillating crystal, or a signal voltage to the control electrode of an electron tube. Also called drive (2).
  • The process by which a particle, such as an electron or atom, moves from a lower state, usually the ground state, to a state with a higher energy level.

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