Multimeters

In the electronics lab, a common piece of test equipment is the multimeter, in which different kinds of meters are combined into a single unit. The volt-ohm-milliammeter (VOM) is the most often used. As its name implies, it combines voltage, resistance, and current measuring capabilities. You should not have trouble envisioning how a single milliammeter can be used for measuring voltage, current, and resistance. The preceding discussions for measurements of these quantities have all included methods in which a current meter can be used to measure the intended quantity.

Commercially available multimeters have certain limits in the values they can measure. The maximum voltage is around 1000 V. The measurement of larger voltages requires special probes and heavily insulated wires, as well as other safety precautions. The maximum current that a common VOM can measure is about 1 A. The maximum measurable resistance is on the order of several megohms or tens of megohms. The lower limit of resistance indication is around 0.1 to 1 Ω.