a device designed to measure small electric currents; the simplest electric meter
A galvanometer is an instrument for detecting and measuring small electric currents.
Or use this long answer: galvanometer , instrument used to determine the presence, direction, and strength of an electric current in a conductor. All galvanometers are based upon the discovery by Hans C. Oersted that a magnetic needle is deflected by the presence of an electric current in a nearby conductor. When an electric current is passing through the conductor, the magnetic needle tends to turn at right angles to the conductor so that its direction is parallel to the lines of induction around the conductor and its north pole points in the direction in which these lines of induction flow. In general, the extent to which the needle turns is dependent upon the strength of the current. In the first galvanometers, a freely turning magnetic needle was hung in a coil of wire; in later versions the magnet was fixed and the coil made movable. Modern galvanometers are of this movable-coil type and are called d'Arsonval galvanometers (after Arsène d'Arsonval, a French physicist). If a pointer is attached to the moving coil so that it passes over a suitably calibrated scale, the galvanometer can be used to measure quantitatively the current passing through it. Such calibrated galvanometers are used in many electrical measuring devices. The DC ammeter , an instrument for measuring direct current, often consists of a calibrated galvanometer through which the current to be measured is made to pass. Since heavy currents would damage the galvanometer, a bypass, or shunt, is provided so that only a certain known percentage of the current passes through the galvanometer. By measuring the known percentage of the current, one arrives at the total current. The DC voltmeter , which can measure direct voltage, consists of a calibrated galvanometer connected in series with a high resistance. To measure the voltage between two points, one connects the voltmeter between them. The current through the galvanometer (and hence the pointer reading) is then proportional to the voltage.
The galvanometer is very sensitive.
Since Galvanometer is a very sensitive instrument therefore it can't measure heavy currents. In order to convert a Galvanometer into an Ammeter, a very low resistance known as "shunt" resistance is connected in parallel to Galvanometer. Value of shunt is so adjusted that most of the current passes through the shunt. In this way a Galvanometer is converted into Ammeter and can measure heavy currents without fully deflected.
A galvanometer with a low resistance shunt in parallel makes an ammeter.
GALVANOMETER detects very small currents in terms of milli amperes so it is said to be called as sensitive
zero
What is the difference between the construction of a moving coil galvanometer and a ballistic galvanometer?
Its a point on the galvanometer where the galvanometer shows no deflection as no current passes through it.
The current is reversed in a galvanometer
because in tangent galvanometer earth magnetic field and magnetic field of magnet inside galvanometer are perpendicular to each other
By attaching a resistance in parallel connection with the galvanometer. Or when a low resistor connected in parallel with galvanometer ,the galvanometer is converted in ammeter. and the resistor is called shunt resistance.
The weston type galvanometer is a moving coil galvanometer in which a pointer is attached to the coil for measuring deflection due to torque .
A galvanometer is used to test an electrical current. A galvanometer can be made using a compass and a thin gauge of wire.
A sensitive galvanometer cannot be stable. Explain Why?
application of Ballistic Galvanometer 1) measurements of electric charges
Zero is the normal position of the galvanometer when there is no detection in process.
The galvanometer is very sensitive.
for the convenience of calculations