A Practical Vacuum-Tube Circuit for the Measurement of Electromotive Force
Samuel B. Ellis, Samuel J. Kiehl · Review of Scientific Instruments · 1933
A sensitive and accurate method is described for measuring electromotive force through large resistances, up to around 100,000 megohms, or for measuring electromotive force in systems which are easily polarized. The measuring instrument is simply and inexpensively constructed of standard parts which are readily available, and in actual use it is convenient, dependable and rugged.