Current Reverse.—A current in the opposite direction to the normal current.
Decimetre.—The tenth part of a metre.
Deflection.—The angle or number of degrees through which the needle of a galvanometer moves when a current is passing through its coils.
Diaphragm.—A porous division between two liquids through which electric current passes.
Duplex Cut-out.—An instrument which enables a spare fuse to be immediately substituted for that melted.
Duty.—A term used to denote the economy of any motor.
Dynamo.—A name given to machines which produce electricity for commercial purposes.
Dynamometer.—An instrument for ascertaining the horse-power absorbed by any machine.
Dyne.—The Unit of force which gives a velocity of 1 centimetre per second to 1 gramme weight after acting for 1 second.
Direct-Current Dynamo.—An electric generator producing currents passing in one direction.