Definition

Noun: A moving-coil galvanometer is a sensitive instrument for detecting or measuring small electric currents. Its operation is based on the force exerted on a movable coil, which carries the current, when it is suspended within a magnetic field. The deflection of the coil is proportional to the current passing through it.

Usage

This term is used specifically in the context of physics and electrical engineering to describe a classic type of analog measuring instrument. - It functions as the core sensing mechanism in many analog ammeters and voltmeters. - Its design is fundamental for understanding electromagnetic principles.

Examples

• The laboratory demonstration used a moving-coil galvanometer to show the magnetic effect of an electric current.
• To measure the tiny current from the photocell, a sensitive moving-coil galvanometer was employed.
• The design of the moving-coil galvanometer, with its coil and permanent magnet, makes it a precise tool for DC measurements.

Advanced Usage

• Historical Context: The moving-coil galvanometer, often associated with the D'Arsonval/Weston type, represented a major advancement in electrical instrumentation due to its linear scale and sensitivity.
• Underlying Principle: The operation relies on the motor principle: a torque acts on a current-carrying coil in a magnetic field, causing it to rotate against a restoring spring.

Variants and Related Words

• Galvanometer (n): The general term for any instrument that detects electric current by its magnetic effects.
• Ballistic galvanometer (n): A type of galvanometer designed to measure the total quantity of electricity (charge) in a transient current pulse, often using a moving-coil design with minimal damping.
• Ammeter (n): A current-measuring instrument that often uses a moving-coil galvanometer as its core movement, with added shunts to handle larger currents.
• Voltmeter (n): An instrument for measuring electrical potential difference, frequently constructed by connecting a high resistance in series with a moving-coil galvanometer.

Synonyms

• D'Arsonval galvanometer
• Weston galvanometer
• Permanent-magnet moving-coil (PMMC) instrument

Related Phrases and Concepts

• "Coil deflection": The angular movement of the coil in a moving-coil galvanometer, which indicates the current strength.
• "Magnetic torque": The rotational force that causes the coil to move, fundamental to the instrument's operation.
• "Analog meter movement": A common description for the moving-coil galvanometer mechanism when used as the display component in a meter.

Noun

1. a galvanometer that is operated by the force exerted by an electric current flowing in a movable coil suspended in a magnetic field