Note on `A Simple Galvanometer with Negative Feedback'
D. K. C. MacDonald · Journal of Scientific Instruments · 1947
Following upon Preston's earlier design of a galvanometer amplifier using a high degree of parallel negative feedback, a simple circuit using series feedback is presented which proves most suitable for measurements of small potentials as in metallic conductivity experiments. It is shown how the performance equations may be quickly derived for both systems, regarding them essentially as error-nullifying servo systems.