<P> For general - purpose digital multimeters, the lowest voltage range is typically several hundred millivolts AC or DC, but the lowest current range may be several hundred microamperes, although instruments with greater current sensitivity are available . Multimeters designed for (mains) "electrical" use instead of general electronics engineering use will typically forego the microamps current ranges . </P> <P> Measurement of low resistance requires lead resistance (measured by touching the test probes together) to be subtracted for best accuracy . This can be done with the "delta", "Zero", or "null" feature of many digital multimeters . </P> <P> The upper end of multimeter measurement ranges varies considerably; measurements over perhaps 600 volts, 10 amperes, or 100 megohms may require a specialized test instrument . </P> <P> Every inline series - connected ammeter, including a multimeter in a current range, has a certain resistance . Most multimeters inherently measure voltage, and pass a current to be measured through a shunt resistance, measuring the voltage developed across it . The voltage drop is known as the burden voltage, specified in volts per ampere . The value can change depending on the range the meter selects, since different ranges usually use different shunt resistors . </P>

What does m stand for on a multimeter