The primary difference between ammeter and galvanometer is that an ammeter displays solely the current’s magnitude, whereas a galvanometer indicates both the current’s direction and magnitude.
What is Ammeter?
An ammeter is a device designed for measuring electrical current within a circuit, typically denoted in amperes (A) after the scientist André-Marie Ampère, from whom it derives its name. This instrument is primarily utilized for measuring currents in the microampere or milliampere range.
In its early forms, ammeters found in laboratories operated based on the Earth’s magnetic field for their functionality.
In 1820, Hans Christian made a groundbreaking observation regarding the relationship between electric currents and magnetic fields. He noticed that when an electric current flowed through a nearby wire, it caused a compass needle to deviate from its northward direction.
This effect was initially measured using a tangent galvanometer, with the Earth’s magnetic field providing the force that brought the pointer back to its positive zero position. Consequently, these instruments could only be effectively used when aligned with the Earth’s magnetic field.
What is Galvanometer?
A Galvanometer is an electromechanical device used for detecting and displaying electrical currents. It operates by producing a rotational movement of a pointer in response to an electric current passing through a coil within a constant magnetic field. This deflection is used to measure the amount of electricity flowing through a circuit.
The principle behind galvanometers involves deflecting a magnetic compass needle near a wire carrying an electric current, a discovery credited to Hans Christian in 1820.
Galvanometers have played a pivotal role in advancing technology and science across various fields. They enabled long-distance communication, including submarine and transatlantic telegraph cables, among other applications.
Ammeter vs Galvanometer
The important difference between an ammeter and a galvanometer is given below::
| Parameter | Ammeter | Galvanometer |
| Definition | It measures both the direct and alternating current. | It is the instrument, which is useful for the detection of the strength as well as the direction of small current flow in a circuit. |
| Instrument Category | It is an electric or mechanical instrument. | It is an electromechanical instrument. |
| Need for magnetic field | It works with or without a magnetic field. | It needs a magnetic field. |
| Accuracy | It is more accurate. | It is less accurate. |
| Nature of Current | It measures both the direct and alternating current. | It measures only direct current. |
| Level of sensitiveness | It is less sensitive. | It is more sensitive. |
| Applications | It is useful in the electrical circuit. | It is useful in the bridge and potentiometer measurements. |
| Direction of current | It does not show the direction of the current. | It shows the direction of the current. |