Overvoltage measurement

The currents measured in the strips as well as the overvoltages measured above the middle of each strip are given in table 3.7. 

Lorenz W (1954) Oscillographic overvoltage measurements. Z Electrochem 58 912-918 (in German)... 

According to the details of Eq. (23-44), off potentials cannot be measured if the diode overvoltage arrester cannot be switched off from the power line momentarily (e.g., by using a time switch). 

B) Apparatus for measurement of overvoltage at an electrode as a function of current density. 

SO that the concentration of [Zn ] under the same conditions will be 10 g-molecule/L. With these ionic concentrations, the deposition potentials of copper and zinc in the absence of any polarization can each be calculated from Eq. (11.1) to be about —1.30 V. It should be mentioned here again that in practice, Eq. (11.1) refers to reversible equilibrium, a condition in which no net reaction takes place. In practice, electrode reactions are irreversible to an extent. This makes the potential of the anode more noble and the cathode potential less noble than their static potentials calculated from (11.1). The overvoltage is a measure of the degree of the irreversibility, and the electrode is said to be polarized or to exhibit overpotential hence, Eq. (11.2). 

Some recent work by E. Newbery1 has provided a considerable number of trustworthy overvoltage determinations which should prove valuable in choosing the proper electrode for any given reduction. By overvoltage is understood the excess back electromotive force above that of a hydrogen electrode in the same electrolyte, and this has been measured by direct comparison with a hydrogen... 

---