Non-magnetic Steel. Alloys of iron incapable of being magnetized. They are composed of iron and manganese, nickel, steel, etc.
Normal. Regular. The average value of observed quantities. Normal current is a regular current without variations.
The force of a current at which a system is intended to work.
Normal Voltage. The same as Normal Current.
North Pole. The north-seeking pole of a magnet.
The pole of a magnet which tends to point to the north, and whence lines of force are assumed to issue on their course to the other pole of the magnet.
O
O. An abbreviation for Ohm.
Oersted’s Discovery. Oersted discovered, in 1820, that a magnetic needle tended to place itself at right angles to a current of electricity. This fundamental principle is the basis of the galvanometer, the dynamo, and the motor.
Ohm. The practical unit of resistance. A legal ohm is the resistance of a column of mercury one square millimetre in cross-sectional area and 106.24 centimetres in length.