Abstract: A multimeter comprising a clip-on device (12) and a Hall-effect measuring circuit (5) for measuring either a direct or an alternating current I. Moreover, the multimeter comprises a voltage-measuring circuit (2) for measuring either a d.c. or an a.c. voltage U as applied to two input/output combination sockets (3, 4). By means of a function transformer (30), a digitizing unit (19), a digital unit (25) and further circuit components which also include a battery-operated power-supply unit (1), the measured current and/or voltage values, by taking into due consideration any stored correcting values as well as such correcting values which result from adjusting measurements, and any circuit-specific constants as already previously stored by the manufacturer, are processed in accordance with predetermined rules for proportioning into display signal-waveform-independent values relating to the current I, the voltage U, the apparent power Ps, the real power Pw, the power factor, the frequency f, and further values.