Ampere W/V. Current can be measured by a multimeter, a device that can measure electrical voltage, current, and resistance. The standard ampere is most accurately realized using a Kibble balance, but is in practice maintained via Ohm's law from the units of electromotive force and resistance, the volt and the ohm, since the latter two can be tied to physical phenomena that are relatively easy to reproduce, the Josephson junction and the quantum Hall effect, respectively. At present, techniques to establish the realization of an ampere have a relative uncertainty of approximately a few parts in 10, and involve realizations of
Open-circuit voltage potential drop across the resistance C. The resistor B does not affect the open-circuit voltage. Since no current is flowing through it, there is no potential drop across it. So we can easily ignore it. Therefore, the potential drop across the resistance C is "V." This is just an example. Many other ways can be used. Open-circuit voltage Open-circuit voltage (abbreviated as OCV or V ) is the difference of electrical potential between two terminals of a device when disconnected from any circuit. There is no external load connected. No external electric current flows between the terminals. Alternatively, the open-circuit