Colour blindlless to Commutator.

Colour blindness. Being unable to tell the difference between certain colours.
Colour burst. A very accurately phased burst of high frequency at the beginning of each scanning line. This determines the colour of the signal.
Colour phase. The proper timing re­lationship within a colour signal. Colour is considered to be in phase when the hue is reproduced cor­rectly or the screen.
Colour sync. A control signal neces­sary for the operation of colour cameras, SEGs, and monitors; con­sists of a 3.58 MHz burst (which sets the colour phase and placement before each line is scanned) and a 3.58 MHz colour subcarrier.
Colts arn. ory press. (Print.) A heavy-duty type of platen press.
Column. (Arch.) A vertical shaft or pillar receiving pressure in the di­rection of its longitudinal axis. (Print.) One of the vertical sections, as on a newspaper page.
Column. Type of loudspeaker enclosure in which rear of drive unit receives resonant bass loading from a column of air. Speaker may be mounted at one end or, in sophisticated versions, some distance from the narrow end of a tapered column.
Combination. (Chern.) Union of two or more elements.
Combination chuck. (Mach.) A uni­versal chuck which may also have
an dependent jaw action.
Combination die. (Mach.) Die so constructed that it both cuts the blank and draws the piece to required shape. A combination of blanking and drawing dies.
Combination drill and counter-sink. (Mach.) Used for centering work to be held between the centers of a lathe. (SEE CENTER DRILL.)
Combination halftone. (Print.) An en­graving consisting of halftone and line values requiring two negatives.
Combination plate. (Print.) Halftone and line work combined and etched on one plate.
Combination pliers. Those adjustable for size of opening by means of a slip joint; having the outer grip scored and the inner grip notched for grasping round objects.
Combination square. (Shopwk.) A square containing bevel protractor, level and center head in addition to a movable square head.
Combination switch. (Elec.) A switch such as is used on automobiles, for controlling both ignition and lights.
Combustion. (Chern.) The chemical union of a combustible substance with oxygen, resulting in the produc­

Combustion chamber. (Auto. Mech.) That space within the cyl­inder and in the cylinder head di­rectly above the piston.
Commercial efficienccy of dynamo. (Elec. ) Determined by dividing the output by the input expressed in per cent: Eff. = ~utput mput
Commercial efficiency of motor. (Elec.) Brake horsepower divided by the electrical horsepower. Or output divided by the input; ex­pressed in per cent.
Commercial flux. A flux sold under a trade name; prepared for use in soldering, brazing, and welding.
Comminute. To reduce solids to minute particles by crushing, grinding, or pulverizing.
Common. Part of circuit or system of connections shared by several components or units, and thus com­mon to them---all. Sometimes and earth or chassis.
Common bass. Stereo reproducing system with derived low frequency mono 'sum' signal fed to single bass loud-speaker, but with conventional UR division at mid and high fre­quencies.
Common bond. (Masonry) Similar to a running bond, but with every fifth, sixth, or seventh course a header course, either full of Flemish, the former being all headers, the latter with headers and stretchers alter­nately.
Common brick. Brick such as is used for rough work or for filling in or backing.
Common collector. See Emitter­ follower.
Common-emitter. Transistor stage in which the emitter is common to both input and output currents. Most usual type of simple amplifier.
Common rafters. (Arch.) Rafters, common to any part of a roof, ex­tending from plate to ridge without a break.
Communicate. To pass information and ideas from one person to an­other.
Commutating pole. (£lee.) An elec­tromagnetic bar inserted between the pole pieces of a dynamo to offset the cross magnetization of the armature currents.
Commutation. (£lee.) A contrivance for reversing the direction of elec­tric current in any circuit.
Commutator. A del'ice used to re\'('rse the direction of current. A motor or a generator commutator consists of a ring of insulated copper bars or
segments mounted upon the shaft and connected to the coils of wire

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