Vulcanized india rubber which by high proportion of sulphur and proper vulcanization has been made hard. It is sometimes distinguished from ebonite as being comparatively light in color, often a dull red, while ebonite is black. For its electrical properties see Ebonite. Both substances have their defects, in producing surface leakage. Washing with weak ammonia, [...]

A voltmeter based on the lines of the quadrant electrometer. It includes two sets of quadrants, each oppositely excited by one of the two parts, whose potential difference is to be determined. They attract each other against a controlling force as of gravity. One form has the two sets poised on horizontal axes, bringing the [...]

The volts at the terminals of a dynamo at full load fall short of their value on open circuit. The difference of the two values are termed lost volts.

A voltmeter in which the current passing through its conductor heats such conductor, causing it to expand. Its expansion is caused to move an index needle. By calibration the movements of the needle are made to correspond to the potential differences producing the actuating currents through it. The magnetic action of the current plays no [...]

A voltmeter for use in running batteries. In one form (Wirt’s) it is constructed for a low range of voltage, reading up to two and a half volts and having exactly one ohm resistance, thus giving the battery some work to do.

An instrument for determining the potential difference of any two points. In many cases it is a calibrated galvanometer wound with a coil of high resistance. The object to be attained is that it shall receive only an insignificant portion of current and that such portion shall suffice to actuate it. If connected in parallel [...]

The legal volt based upon the legal ohm. It is equal to 1.00112 B. A. volt.

A form of easily read voltameter for use in electric light stations and for similar work.

The unit of electric work; the watt-second; it is equivalent to 1.0E7     ergs. .24068   gram degree C. (calorie) .737337  foot lbs., .00134   horse power seconds.

The volt based upon the congress or legal ohm; the legal volt.