A microphone design in which sound causes the movement of a plate (diaphragm) in relation to a fixed backplate. This movement causes a change in capacitance (electrical charge) which is translated to voltage by an amplifier. Therefore, condenser microphones require electrical power to operate. Microphones designed for video production can usually be powered using phantom power from a camera, mixer, or recorder. Some condenser microphones have an onboard power supply and thus require the use of a battery.