An item utilizing electron tubes, transistors, and/or semiconductor devices forming rectifier and electronic keying or switching circuitry, that is inserted between a load designed to operate at one frequency and a power supply line rated at another frequency. For items performing the same function by heterodyne action at either radio or power line frequencies, see CONVERTER, FREQUENCY, ELECTRONIC. For items that perform this function by means of rotary equipment, see MOTOR-GENERATOR. See also DIVIDER-MULTIPLIER, FREQUENCY; FREQUENCY DIVIDER; FREQUENCY MULTIPLIER and MIXER STAGE, FREQUENCY.
