The purpose of this circuit is to increase the sensitivity of a galvanometer, making it possible to operate with very low currents or as a sensitive continuity indicator. The galvanometer can be a microammeter or a milliammeter and the resistor R1 must be dimensioned to obtain a good performance. We can connect a 1k resistor in series with it for easier adjustment. The circuit is from a book by Newton C. Braga.
