Neets Master Glossary

1-57 PRIMARIES (OF LIGHT)—The three primary colors of light from which all other colors can be derived. The colors are red, green, and blue [10]. PRIMARY CELL—An electrochemical cell in which the chemical action eats away one of the electrodes, usually the negative electrode [1]. PRIMARY LOOP—In a cooling system, the primary source of cooling for the distilled water [18]. PRIMARY WINDING—The winding of a transformer connected to the electrical source [2]. PRIME MOVER—The source of the turning force applied to the rotor of a generator. This may be an electric motor, a gasoline engine, a steam turbine, and so forth [5]. PRINTED CIRCUIT BOARD—A flat, insulating surface upon which printed wiring and miniaturized components are connected in a predetermined design and attached to a common base [7] [14]. PRISM—A triangular-shaped glass that refracts and disperses light waves into component wavelengths [10]. PROBE COUPLER—A resonant conductor placed in a waveguide or cavity to insert or extract energy [18]. PROGRAMMED TRACKING—The method that uses known satellite orbital parameters to generate antenna pointing angles [17]. PROPAGATION—Waves traveling through a medium [10]. PULSE—Signal characterized by a steep rise from and decay toward an initial level [9] [12]. PULSE-AMPLITUDE MODULATION (PAM)—Pulse modulation in which the amplitude of the pulses is varied by the modulating signal [12]. PULSE-CODE MODULATION (PCM)—A modulation system in which the standard values of a quantized wave are indicated by a series of coded pulses [12]. PULSE DURATION (PD)—The period of time during which a pulse is present [12]. PULSE-DURATION MODULATION (PDM)—Pulse modulation in which the time duration of the pulses is changed by the modulating signal [12]. PULSE-FORMING NETWORK (PFN)—An lc network that alternately stores and releases energy in an approximately rectangular wave [12] [18]. PULSE-FREQUENCY MODULATION (PFM)—Pulse modulation in which the modulating voltage varies the repetition rate of a pulse train [12]. PULSE MODULATION—A form of modulation in which one of the characteristics of a pulse train is varied [12]. PULSE OSCILLATOR—A sine-wave oscillator that is turned on and off at specific times. Also known as a ringing oscillator [9]. PULSE-POSITION MODULATION (PPM)—Pulse modulation in which the position of the pulses is varied by the modulating voltage [12].