INTRODUCTION The 7140 Digital Multimeter (DMM) combines the advantages of a compact and versatile multimeter with the precision and convenience of a digital instrument. Automatic range selection and polarity decision give rapid readings. The complete absence of range switching enables the user to concentrate on the task in hand and apart from selecting the actual measurement mode required all other measurement decisions are undertaken automatically, so reducing the risk of damage to the user’s equipment, as well as to the DMM.