Search results
Results from the WOW.Com Content Network
An early D'Arsonval galvanometer showing magnet and rotating coil. A galvanometer is an electromechanical measuring instrument for electric current.Early galvanometers were uncalibrated, but improved versions, called ammeters, were calibrated and could measure the flow of current more precisely.
A moving coil galvanometer can be used as a voltmeter by inserting a resistor in series with the instrument. The galvanometer has a coil of fine wire suspended in a strong magnetic field. When an electric current is applied, the interaction of the magnetic field of the coil and of the stationary magnet creates a torque, tending to make the coil ...
The first moving-pointer current-detecting device was the galvanometer in 1820. These were used to measure resistance and voltage by using a Wheatstone bridge, and comparing the unknown quantity to a reference voltage or resistance. While useful in the lab, the devices were very slow and impractical in the field.
Subsequent designs of ohmmeter provided a small battery to apply a voltage to a resistance via a galvanometer to measure the current through the resistance (battery, galvanometer and resistance all connected in series). The scale of the galvanometer was marked in ohms, because the fixed voltage from the battery assured that as resistance is ...
When a voltmeter is connected between two different types of metal, it measures the potential difference corrected for the different atomic environments. [6] The quantity measured by a voltmeter is called electrochemical potential or fermi level , while the pure unadjusted electric potential, V , is sometimes called the Galvani potential , ϕ .
A modern electrometer is a highly sensitive electronic voltmeter whose input impedance is so high that the current flowing into it can be considered, for most practical purposes, to be zero. The actual value of input resistance for modern electronic electrometers is around 10 14 Ω, compared to around 10 10 Ω for nanovoltmeters. [ 9 ]
What do you think when you see the Amazon Prime logo on a product? Most people, even the most devoted Amazon users, will think it's a verified seller affiliated with the ecomm giant -- but that's ...
Voltmeter: Measures the potential difference between two points in a circuit. (Includes: DVM and VTVM) VU meter: Measures the level of AF signals in Volume units Cathode Ray Oscilloscope (CRO) Check transistor