potential to Power feed
uses in the arts, .but its many salts I are of great value.
Potential. (Elec.) An electrical state or the electrical state of a point. It is measured by the work done in bringing a unit charge from an infinite distance up to the point. It is measured in practical units called volts. (phys.) A condition at a point in space, due to local attraction or repuhion, such that a mass, electric charge, etc., at such point becomes capable of doing work.
Potential difference. (Elec.) The difference in the ~lectrical state of two points, measured in volts.
Potential energy. (Phys.) Stored energy or energy of position.
Potentiometer. (Elec.)An instrument used for comparing voltages with a constant standard; also a fonn of rheostat.
Pot life. (Plast.) See Working life.
Potters wheel. (Ceram.) A disk which rotates in a horizontal plane on which potters's clay is thrown for shaping by hand.
Pottery. Earthenware or porcelain, or the factory in which it is made.
Pounce. (Draft.) The fine powder sometimes applied to the surface of tracing linen to facilitate inking.
Pound. (Troy weight) Twelve ounces; (avoirdupois weight) sixteen ounces.
powder metallurgy. This process is accomplished without melting. The fine powdered metals are placed in a steel mold and sub jected to heavy pressure, producing a fragile metal shape which under heat-treatment results in a perfect alloy. The method is well adapted to the making of alloys of metals or nonmetals having a great difference in metling temperature.
Power. (Elec.) The unit of electric power is the watt, in which is measured the rate of work done by electricity in motion. (Mech.) The rate of working or expending energy. In machanics power is measured: force x distance + time. It is expressed in footpounds per minute or second. (Phys.) The rate at which work is perfonned or the amount of work done in a unit of time.
Power amplifier. (~adio.) A type of. amplifer used to deliver a large amount of power to the loud speaker or to an antenna.
Power brakes. (Auto. Mech.) Brakes operated hydraulically through a booster system.
Power factor. (Elec.) The ratio of the true power (watts as read by a wattmeter) to the apparent power (volts times amperes as read by a voltmeter and ammeter respectively) f = true power (W) p.. apparent power (V x A)
Power feed. (Mech.) The automatic Power hammer to precision grinding feed of a lathe, planer, screw-cutting, or other machine.
Power hammer. A hammer operated by air, water, or mechanical power, used on heavy work.
Power landing. (Aero.) Any landing during which the engine is kept running at more than idling speed. ..
Power loading. (Aero.) The gross weight of an airplane fully loaded, divided by the normal brake horsepower of the engine computed for air of standard density unless otherwise stated.
Power pack. (Elec.) A device to supply the necessary filament or heater power, and also the plate power and grid bias for the operation of a radio set, publicaddress system, etc. In some cases, a direct current for the dynamicspeaker field is supplied.
Power plant. (Auto.) Engine with fuel, carburetion, ignition, cooling, and lubrication 'systems. (Mach.) The building boilers, engines, electric generators, etc., for generating and distributing power, as for a factory.
Power steering. (Auto. Mech.) Permits free steering when the engine is running; hydraulically operated through a booster built into the steering unit attached to the steering linkage.
Power stroke. (Atuo.) (I) The arc of crrankshaft travel while the pressure of ignited gases is exerted on the piston. (2) The piston stroke on which the engine is deliverin power.
Power transformer. (Elec.) A device for connecting power from a high voltage and low current to a low voltage and high- current, or vice versa, the amount of power so changed remaining theoretically the same. The frequency in which these are used is usuaIly 50 cycles.
Power tube. (Radio) The vacuum tube used in the last stage of the AF (audio frequency) amp lifer. Provides large AF for the speaker operation.
Power unit. (Elec.) The watt is the unit of power in electrical circuits. The product of the voltage times the amperage gives the wattage.
Power venturi. (Aero.) A venturitube used to operate gyroscopic tUrn indicators and other instruments.
Practice. (I) To do, carryon, act, or exercise. (2) To foIl ow or work at, as a profession.
Pratt truss. A popular form of truss for both roof and bridge construction. The vertical members are in compression and the diagonals in tension.
Precarious. Risky; doubtful; perlious.
Precipitate. (Plast.) A solid substance thrown out of solution as the result ofa chemical change effected by addition of a reagent. To separate a substance from a solution by chemical action' of a reagent.
Precision grinding. (Mach.) Machine grinding in which the to
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