Digital Multimeters, also referred to as "digital-multi-meters" or abbreviated as DMM, combines several functions in one unit, enabling users to measure current, voltage, and resistance. With these modern multimeters or multitesters, the signal under test is converted to a digital voltage and an amplifier with an electronically controlled gain preconditions the signal. Because the digital display indicates a quantity as a number, common errors when viewing a reading which normally occurs with analog multimeters are prevented, resulting to a more accurate reading.