A digital technique for converting a measured analog quantity to a precise digital equivalent, for display as a numerical value. During a fixed interval of time, the output of an integrating circuit rises linearly at a rate proportional to the measured analog input quantity. The circuit input is then switched to a precise reference-voltage source of opposite polarity, causing the output to descend at a fixed rate, while a counting circuit counts clock pulses delivered by an internal pulse generator. As the integrator output reaches its base level, the count is terminated; the total count (numerically equivalent to the analog input quantity) is then displayed in a digital readout as a voltage, current, resistance, or other parametric quantity.