Digital Multimeters

A conventional manual multimeter.

There is a difference between a digital manual multimeter and a digital autoranging multimeter. They both get the job done. The difference lies in the convenience of having a meter that automatically adjusts to the voltage or ohm setting needed to test the component or circuit.

With a conventional manual multimeter, the technician would either know before hand or rotate the dial to find the appropriate range, usually starting at a high value, and moving the dial down until seeing the range they were looking for. If an autoranging multimeter is used, the meter will find the range and indicate it on the screen for the technician. This is great when working with sensors, circuit boards and resistors. Resistors are banded with color codes that often require a chart to identify. These can be easily identified with an autoranging multimeter.

Most autoranging digital meters contain fuses or circuit protection for today’s sensitive circuits. This is a big plus over the older analog dial meters used in the past. If the technician were looking for 1.35 kiloohms, the meter would automatically set to kiloohms and indicate this number on the screen. An improperly set manual meter set to ohms may indicate 0.001 confusing the operator and the test results.

Multimeter reading explanation.

In the illustration above the technician has set a manual multimeter to kiloohms and retrieved a reading of .016 K ohms. Since the meter is set for kiloohms, it is .016 x (K) or times (1000) equals 16 ohms. Just move the decimal three positions to the right. They are equal. The technician could have moved the manual lever to the ohms position and retrieved 16 Ohms. If the meter displayed .009 kiloohms, it would be indicating 9 ohms of resistance. They too are equal.