Cinquefoil to Class-d

Cinquefoil. (Arch.) A five leaved rosette or ornament.
Circassian walnut. (Wood) A fawn­coloured walnut with dark­co loured streaks. The wood was very extensively used in furniture manufactured from 1900 to the beginning of the World War I.
Circle. (Math.) A plane figure bounded by a curved line every point of which is equally distant from a fixed poinrwithin called the center. The circumference of a cir­cle is divided into 360 equal parts, called degrees. (SEE CIRCULAR MEASURE.) Area = radius squared x 3.1416 or diameter quared x 0.7854.
Circle marker. (Aero.) A circular band marking the approximate center of the landing area or the in­tersection of the principal landing strips on an airport or landing field.
Circle trowel. (Plaster.) A plaster­ers trowel made with either con-. cave or convex blade for working on curved surfaces.
Circuit. (Elec.) The course followed by an.electric current passing from its source through a succession of conductors and back to its starting point.
Circuit breaker. (Elec.) A switch, usually automatjc, which opens to stop the flow of current.
Circuit, printed. A method of cir­cuit wiring in which the conduc­tors consist of copper strips secured upon a sheet of insulator material.

Circuit, series. A circuit in which the loads are connected into one wire or conductor of the power line in a "one after the other" fashion.
Circuit short. A circuit which con­tains a defect that causes electrons to follow a path 14at presents much less resistance than is normal.
Circular and angular measure. . 60 seconds (") = I minute (')
60 minutes = I degre e) 90 degrees = I quadrant 4 quadrants = 1 circle of
circumference
Circular loom. (Elec.) A fire-resist­ing, flexible, coated, nonmetallic tubing slipped over electric wires for additional insulation.
Circular mil. (Elec. ) The area of a cir­cle one mil in diameter; used as a unit in measuring the cross sections of wires.
Circular milling machine. (Mach.) A vertical-type, continuous milling machine in which both table and cutter rotate.
Circular pitch. (Gear.) The distance from the center of one tooth to the center of the next, measured on the pitch line.
Circular saw. A saw whose teeth are spaced around the edge of a circular disk running upon a central arbor.
Circumference. The length of a line which forms a circle. (Math.) c. of circle = diameter x 3.1416.
Circumscribe. To enclose within cer­tain lines or boundaries. To draw around or outside of.
Ciseleur. (FIlI.n.) An engraver or maker of metal ornaments

Citric acid. ( Chem.) A tribasic acid extracted from lemons or other cit­rus fruits, as a white crystalline substance having a pleasant sour taste. Used in medicines, flavour­ing extracts, confectionery, etc.
Civil engineer. One whose work in­cludes design, construction, and maintenance of public works, high-ways, railroads, bridges, steel frame-work of buildings, etc.
Civil service. The appointive employment in go.vernment position of civilian personnel. As a rule civil-service employees are selected from an eligible list prepared from an examination. They hold office so long as they are efficient and comply with all rules.
Clamp. (Carp. and Mach.) A tool for holding portions of work to­gether, both in wood and metal.
Clamp coupling. (Mech.) A shaft coupling made in two or more parts, and clamped by means of traDsverse bolts.
Clamp dog. (Mach.) A lathe carrier consisting of two jaws and two bolts which prmit a clamping on the work.
Clamping ba.rs. (Fdry.) Those bars either adjustable or solid used for clamping the parts of a mold together to prevent a separation by . the expansion of gases. .
Clamping screw. Any screw by whichpieces of work are pinched or held together: A screw which clamps.
Clapboard. (Arch.) A lapping weather-board used for siding.
Clapper box. (Mach.) The swinging part of the tool-holding device on a sbaper or planer which permits the tool to ride freely over the work on the return stroke.
Clap post. (Furn.) The upright post of a cupboard on which the door "claps" or closes.
Class-a. Power amplifier in which all the valves or transistors operate on linear portions of their transfer char­acteristics all the time. Circuit draws constant current from power supply irrespective of signal level.
Class-ab. Power amplifier in which valves or transistors operate on lin­ear portions of their transfer char': acteristics at low amplitudes (Class­ A), Changing to regime in which. positive and negative portions of the signal wave form are shared between push-pull components at high
Class-b. Type of power amplifier in which valves or transistors (usually output pair) split positive andnega­tive portions of the signal waveform between them, each operating from low initial current.point. Current drawn by circuit from power supply rises with signal level. .
Class-d. Power amplifier employing PWM