Testing ourselves [The quiz for this issue]

Abstract

Poses questions relating to accuracy, resolution, and sensitivity of a digital multimeter with given characteristics. A multi-meter measures voltage, current, and resistance. It is a customary name for an instrument that puts a voltmeter, an ammeter, and an ohmmeter together into one device. Initially, these instruments were analog, but digital multi-meters have been replacing analog meters for some time. Digital multi-meters are usually specified according to the number of digits in the display. Suppose you measure 5 V with a three-digit multi-meter. It displays anything between 4.95 V to 5.05 V if the accuracy is plusmn1% (10.05 V). With the same accuracy and a four-digit multi-meter, the output is anything in the range of 4.950 V to 5.050 V. High-digit, high-accuracy multi-meters are more attractive, but expensive.