Electrical current measuring

I is electric current, measured in amperes (A). It is coulombs per second moving past a point in the circuit. R is resistance in ohms (ft). Units A = V/il. 

The formula is derived as follows Electrical current, measured in amperes, is the rate of flow of electrical charge (coulombs), by definition, it is... 

The net electrical current measured in the external circuit is due to both oxidation and reduction processes taking part in the whole electrochemical system of two electrodes. In order to study electrcchemical reactions in a controlled way, the processes taking place at only one electrode need be considered and the experiment must be designed for that purpose, making negligible the electrokinetics at the counterelectrode. 

Before addressing the rate issue we need to understand the way in which such rates are measured, keeping in mind that the observable in a typical experiment is electrical current measured as a function of voltage. 

The drift of electrons within a conductor is known as an electric current, measured in amperes and given the symbol /,... 

For an electrical current (measured in amperes) to flow in a circuit it requires pressure (measured in voltage). As it flows it encounters resistance from the circuit and apparatus and this characteristic is measured in ohms. 

The size of the electric current measured by this device tells us the abundance of the species. 

Passive/active measurement. Most measiu ements involve the introduction of energy into the formation in a controlled way. The response from the rock is recorded and used as input to interpretation. Sometimes there is natural energy, already present as the result of processes in the rock, or as a result of the disturbances of drilling. In particular the presence of water or mud with a relatively low salt concentration causes a spontaneous flow of electric current. Measurement of the associated potential difference is the earliest form of well logging as performed by the Schlumberger brothers in the 1920 s [112]. 

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