Fig. 180. THEORY OF DIFFERENTIAL GALVANOMETER.
Fig. 181. DIFFERENTIAL GALVANOMETER.
Galvanometer, Direct Reading.
A calibrated galvanometer, whose scale is graduated by volts or amperes,
instead of degrees.
Galvanometer, Marine. (Sir William Thomson's.)
A galvanometer of the reflecting type, for use on shipboard. A fibre
suspension is adopted for the needle. The fibre is attached to a fixed
support at one end and to a spring at the other, and the needle is
suspended by its centre of gravity. This secures it to a considerable
extent from disturbance due to the rolling of the ship. A thick iron box
encloses the needle, etc., to cut off any magnetic action from the ship.
(See Galvanometer, Reflecting.)
Galvanometer, Potential.
A galvanometer wound with fine German silver wire to secure high
resistance used for determination of potential difference.
Galvanometer, Proportional.
A galvanometer so constructed that the deflections of its index are
proportional to the current passing. It is made by causing the
deflecting force to increase as the needle is deflected, more and more,
or by causing the restitutive force to diminish under like conditions,
or by both. The condition is obtained in some cases by the shape and
position of the deflecting coils.
Galvanometer, Quantity.
A galvanometer for determining quantities of electricity, by the
deflections produced by discharging the quantities through their coils.
It is a ballistic galvanometer with very little or no damping.