A galvanometer is a type of ammeter: an instrument for detecting and measuring electric current. It is an analog electromechanical transducer that produces a rotary deflection of some type of pointer in response to electric current flowing through its coil. The term has expanded to include uses of the same mechanism in recording, positioning, and servomechanism equipment. Extremely sensitive measuring equipment once used mirror galvanometers that substituted a mirror for the pointer. A beam of light reflected from the mirror acted as a long, massless pointer. Such instruments were used as receivers for early trans-Atlantic telegraph systems, for instance. The moving beam of light could also be used to make a record on a moving photographic film, producing a graph of current versus time, in a device called an oscillograph. Today the main type of galvanometer mechanism still used is the moving coil D'Arsonval/Weston mechanism, which is used in traditional analog meters.
A tangent galvanometer is an early measuring instrument used for the measurement of electric current. It works by using a compass needle to compare a magnetic field generated by the unknown current to the magnetic field of the Earth. It gets its name from its operating principle, the tangent law of magnetism, which states that the tangent of the angle a compass needle makes is proportional to the ratio of the strengths of the two perpendicular magnetic fields. It was first described by Claude Pouillet in 1837.
A tangent galvanometer is an early measuring instrument used for the measurement of electric current. It works by using a compass needle to compare a magnetic field generated by the unknown current to the magnetic field of the Earth. It gets its name from its operating principle, the tangent law of magnetism, which states that the tangent of the..
From the Philip Harris catalogue, 50th ed., 1950:
"6779 GALVANOMETER, REFLECTING, MOVING COIL, APERIODIC orBALLISTIC. This galvanometwer comprises a moving coil system with a 1 cm. diameter concave mirror, suspended between the poles of a powerful permanent magnet by means of a phosphor bronze strip attached to an adjustable torsion head. Arrestment is obtained by depression of t..
Unbranded tangent galvanometer, wood construction base & frame. Nice condition except for crack in coil former on one side, near bottom (not very big), and small chip out of wood case of compass, on top edge. Compass scale marked in degrees, 0-90 in 4 quadrants. Coil turns 3, 12 & 50. Detailled specifications e.g.thicknesses of the copper wire, mean diameter etc written on underside in ..
The integrator is in reality a fluxmeter, which may be defined as a moving coil galvanometer specially designed for the measurement of magnetic fields, its deflections being determined solely by the total quantity of electricity discharged through the moving coil and being practically independent of the rate at which the discharge takes place. The special design of the integrator is such that i..
We are accustomed to the word galvanometer, which indicates the strength of an electric current. The Galvanoscope is an earlier instrument, which shows the presence of the current and gives only a rough indication of its magnitude
The basic galvanoscope has only a single turn of wire to set up the magnetic field which turns the magnetic needle. It can be made more sensitive by ..
A mirror galvanometer is a mechanical meter that senses electric current, except that instead of moving a needle, it moves a mirror. The mirror reflects a beam of light, which projects onto a meter, and acts as a long, weightless, massless pointer. In 1826, Johann Christian Poggendorff developed the mirror galvanometer for detecting electric currents. The apparatus is also known as a spot galva..
