Galvanometer, Vertical.
A galvanometer whose needle is mounted on a horizontal axis and is
deflected in a vertical plane. One of the poles is weighted to keep it
normally vertical, representing the control. It is not used for accurate
work.
Synonym--Upright Galvanometer.
Fig. 187. VERTICAL GALVANOMETER.
Galvanometer, Volt- and Ampere-meter.
A galvanometer of Sir William Thomson's invention embodying the tangent
principle, and having its sensibility adjustable by moving the magnetic
needle horizontally along a scale (the "meter") towards or away from the
coil. A curved magnet is used to adjust the control. The leads are
twisted to prevent induction.
The instrument is made with a high resistance coil for voltage
determinations, and with a low resistance coil for amperage
determinations.
At one end of a long base board a vertical coil with its plane at right
angles to the axis of the board is mounted. A scale (the "meter" of the
name) runs down the centre of the board. A groove also runs down the
centre. The magnetic needle is contained in a quadrant-shaped
glass-covered box which slides up and down the groove. A number of short
parallel needles mounted together, with an aluminum pointer are used.
Fig. 188. SIR WILLIAM THOMSON'S AMPERE-METER GALVANOMETER.