(1) Dissipation of radio or sound waves as they interact with matter. (2) The absorbing of light waves without reflection or refraction [10].
ABSORPTION WAVEMETER
An instrument used to measure audio frequencies [16].
ACCELERATING ANODE
An electrode charged several thousand volts positive and used to accelerate electrons toward the front of a cathode-ray tube [6].
ACCELERATION SERVOSYSTEM
A servosystem that controls the acceleration (rate of change in velocity) of a load [15].
ACCELEROMETER
A device that measures the acceleration to which it is subjected and develops a signal proportional to it [15].
ACCEPTOR IMPURITY
An impurity which, when added to a semiconductor, accepts one electron from a neighboring atom and creates a hole in the lattice structure of the crystal. Also called TRIVALENT IMPURITY [7].
ACORN TUBE
A very small tube with closely spaced electrodes and no base. The tube is connected to its circuits by short wire pins that are sealed in a glass or ceramic envelope. The acorn tube is used in low-power uhf circuits [6].
ACOUSTICS
The science of sound [10].
ACQUISITION
Operational phase of a fire-control or track radar during which the radar system searches a small volume of space in a prearranged pattern [18].
ACTIVE SATELLITE
A satellite that amplifies the received signal and retransmits it back to earth [17].