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The amount of electricity that has passed through the system can then be determined from the volume of gas. Thomas Edison used voltameters as electricity meters.. A Hofmann voltameter is often used as a demonstration of stoichiometric principles, as the two-to-one ratio of the volumes of hydrogen and oxygen gas produced by the apparatus illustrates the chemical formula of water, H 2 O.
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 negligible current from the circuit.
High-precision laboratory measurements of electrical quantities are used in experiments to determine fundamental physical properties such as the charge of the electron or the speed of light, and in the definition of the units for electrical measurements, with precision in some cases on the order of a few parts per million. Less precise ...
An electrostatic voltmeter uses the attraction force between two charged surfaces to create a deflection of a pointer directly calibrated in volts. Since the attraction force is the same regardless of the polarity of the charged surfaces (as long as the charge is opposite), the electrostatic voltmeter can measure DC voltages of either polarity.
Any meter will load the circuit under test to some extent. For example, a multimeter using a moving coil movement with full-scale deflection current of 50 microamps (μA), the highest sensitivity commonly available, must draw at least 50 μA from the circuit under test for the meter to reach the top end of its scale. This may load a high ...
A voltameter or coulometer is a scientific instrument used for measuring electric charge (quantity of electricity) through electrolytic action. The SI unit of electric charge is the coulomb. The voltameter should not be confused with a voltmeter, which measures electric potential.
Action describes energy summed up over the time a process lasts (time integral over energy). Its dimension is the same as that of an angular momentum.. A phototube provides a voltage measurement which permits the calculation of the quantized action (Planck constant) of light.
The method was described by Johann Christian Poggendorff around 1841 and became a standard laboratory measuring technique. [1] In this arrangement, a fraction of a known voltage from a resistive slide wire is compared with an unknown voltage by means of a galvanometer. The sliding contact or wiper of the potentiometer is adjusted and the ...