Neets Master Glossary

1-30 GENERAL PURPOSE ELECTRONIC TEST EQUIPMENT (GPETE)—Test equipment that has the capability, without modification, to generate, modify, or measure a range of electronic functions required to test several equipments or systems of basically different designs [14] [16]. GENERATOR—A machine that converts mechanical energy to electrical energy by applying the principle of magnetic induction. A machine that produces ac or dc voltage, depending on the original design [5]. GENERATOR END—See INPUT END [10]. GERMANIUM—A grayish-white metal having semiconductor properties [7]. GETTER—An alkali metal introduced into a vacuum tube during manufacture. It is fired after the tube has been evacuated to react chemically with (and eliminate) any remaining gases [6]. GIMBAL—A mechanical frame, with two perpendicular intersecting axes of rotation, used to support and furnish a gyro wheel with the necessary freedom to tilt in any direction [15]. GLOW DISCHARGE—Discharge of electricity through a gas in an electron tube [18]. GRAMME-RING ARMATURE—An inefficient type of armature winding in which many of the turns are shielded from the field by its own iron ring [5]. GRAPH—A pictorial presentation of the relation between two or more variable quantities, such as between an applied voltage and the current it produces in a circuit [1]. GRID BIAS—A constant fixed potential applied between the grid and the cathode of a vacuum tube to establish an operating point [6]. GRID CURRENT—The current that flows in the grid-to-cathode circuit of a vacuum tube [6]. GRID-GAP TUNING—A method of changing the center frequency of a resonant cavity by physically changing the distance between the cavity grids [11]. GRID-LEAK BIAS—A self-bias provided by a high resistance connected across the grid capacitor or between the grid and cathode [6]. GROUND—(1) The point in a circuit used as a common reference point for measuring purposes. (2) To connect some point of an electrical circuit or some item of electrical equipment to earth or to the conducting medium used in lieu thereof [13]. GROUND CLUTTER—Unwanted echoes, from surrounding land masses, that appear on a radar indicator [18]. GROUND-CONTROLLED APPROACH—A radar system used to guide aircraft to safe landings in poor visibility conditions [18]. GROUND PLANE—The portion of a ground-plane antenna that acts as ground [10]. GROUND-PLANE ANTENNA—A type of antenna that uses a ground plane as a simulated ground to produce low-angle radiation [10]. GROUND PLANES—Copper planes used to minimize interference between circuits and from external sources [14]. GROUND POTENTIAL—Zero potential with respect to the ground or earth [1].