It was invented in 1836 by John Frederic Daniell, a British chemist and meteorologist.
in diameter, to a total resistance of zoo ohms. The actual current required to work the instrument is 3.3 milliamperes (equivalent approximately to the current given by 1 Daniell cell through 3300 ohms), but in practice a current of to milliamperes is allowed.
Thus in the Daniell cell the dissolution of copper as well as of zinc would increase the loss in available energy.
Considered thermodynamically, voltaic cells must be divided into reversible and non-reversible systems. If the slow processes of diffusion be ignored, the Daniell cell already described may be taken as a type of a reversible cell.
Other voltaic standards of electromotive force are in use, such as the Weston cadmium cell, the Helmholtz calomel cell, and the standard Daniell cell.
In cases when great accuracy is not required, a Daniell cell can be used as a standard of electromotive force.