The 7045 is essentially a voltage measuring device. Where necessary, multimeter inputs must be converted into a dc voltage level and suitably scaled prior to analogue to digital conversion. This process is carried out in the Signal Conditioning Section. The Analogue to Digital (A-to-D) Converter produces two balanced pulse trains at its output. Any measured input causes the pulse width of one of the trains to increase, with a proportionate decrease in the width of the other; the nett result is processed in the Digital Section of the multimeter. This section includes a clock circuit. Pulses from the A-to-D Converter provide a clock-enable to a synchronous counter, thus a count is produced proportional to the measured input. The Digital Section also exercises control over the analogue circuitry with regard to range decision and control of the measurement function. Power supplies for the multimeter are derived from a mains operated transformer with provision made for either 230 volts or 115 volt operation. A Battery Unit, when fitted with optional cells, provides an alternative power source.