Abstract: A substantially non-loading circuit for measuring voltages in a range with relatively high upper limit uses a resistive voltage divider for scaling down these voltages for application to a digital voltmeter capable of measuring voltages in a range with relatively low upper limit. The loading that the input circuit of the resistive potential divider would place on the circuit being measured is reduced by placing the loading of the potential divider input circuit on an electrically adjustable voltage supply, rather than the circuit being measured. The current loading on the circuit being measured is sensed; and the output voltage of this supply is automatically adjusted by feedback to reduce the sensed circuit. In this way, loading of the circuit being measured is reduced, thus avoiding undesirable reduction of the voltage across the circuit owing to its being loaded.