Voltmeter
Videos
A voltmeter is an instrument used for measuring electric potential difference between two points in an electric circuit. It is connected in parallel. It usually has a high resistance so that it takes
Demonstration analog voltmeter
Two digital voltmeters. Note the 40 microvolt difference between the two measurements, an offset of 34 parts per million.
Galvanometer
Videos
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 f
Voltmeter
…takes negligible current from the circuit. Analog voltmeters move a pointer across a scale in proportion to the voltage measured and can be built from a galvanometer and series resistor. Meters using amplifiers can measure tiny voltages of microvolts or less. Digital voltmeters give a numerical display of voltage…
An early D'Arsonval galvanometer showing magnet and rotating coil
Close-up view (rear) of a permanent magnet type moving coil meter
Closed-loop galvanometer-driven laser scanning mirror
A galvanometer mechanism (center part), used in an automatic exposure unit of an 8 mm film camera, together with a photoresistor (seen in the hole on top of the leftpart).