Moving Iron Instruments - Voltmeter and AmmeterVoltmeters and ammeters measure the voltage and current, respectively, of a circuit. Some meters in automobile dashboards, digital cameras, cell phones, and tuner-amplifiers are voltmeters or ammeters. Voltmeters and Ammeters : A brief introduction to voltmeters and ammeters for introductory physics students. A voltmeter is an instrument that measures the difference in electrical potential between two points in an electric circuit. Any measurement that can be converted to voltage can be displayed on a meter that is properly calibrated; such measurements include pressure, temperature, and flow. This is necessary because objects in parallel experience the same potential difference.
How to find Ammeter and Voltmeter reading - How are ammeter and voltmeter connected-Kisembo Academy
Ammeter Working Principle and Types of Ammeter
The major difference between the ammeter and the voltmeter is that the ammeter measures the flow of current, whereas the voltmeter measures the emf or voltage across any two points of the electrical circuit. Electricity is measured in two ways. The current and voltage of the circuit are measured through ammeter and voltmeter. The galvanometer uses a coil which is placed between the magnet. When the current flows through the coils, it becomes deflected. The deflection of the coils depends on the charge passing through it.
Meter is an instrument which can measure a particular quantity. As we know, the unit of current is Ampere. Ammeter means Ampere-meter which measures ampere value. Ampere is the unit of current so an ammeter is a meter or an instrument which measures current. The main principle of ammeter is that it must have a very low resistance and also inductive reactance.
Introduction of Ammeter
A voltmeter is an instrument used for measuring electrical potential difference between two points in an electric circuit. Analog voltmeters move a pointer across a scale in proportion to the voltage of the circuit; digital voltmeters give a numerical display of voltage by use of an analog to digital converter. Voltmeters are made in a wide range of styles. Instruments permanently mounted in a panel are used to monitor generators or other fixed apparatus. Portable instruments, usually equipped to also measure current and resistance in the form of a multimeter , are standard test instruments used in electrical and electronics work.
Moving-iron instruments are generally used to measure alternating voltages and currents. In moving-iron instruments the movable system consists of one or more pieces of specially-shaped soft iron, which are so pivoted as to be acted upon by the magnetic field produced by the current in coil. In repulsion type moving—iron instrument consists of two cylindrical soft iron vanes mounted within a fixed current-carrying coil. One iron vane is held fixed to the coil frame and other is free to rotate, carrying with it the pointer shaft. Two irons lie in the magnetic field produced by the coil that consists of only few turns if the instrument is an ammeter or of many turns if the instrument is a voltmeter. Current in the coil induces both vanes to become magnetized and repulsion between the similarly magnetized vanes produces a proportional rotation.