An improved circuit for the direct current amplifying valve of a valve-voltmeter
R. E. Burgess · Journal of Scientific Instruments · 1938
In this note it is shown that the dependence of calibration of a valve voltmeter, using a direct current operated amplifying valve, upon the anode battery voltage may be considerably reduced by the correct choice of galvanometer resistance with respect to the valve characteristics. Details of the method are given in the paper together with a sample of results showing the extent to which changes of calibration can be minimised in practice.