Operating Methods of Analog Multimeters
(1) Jack selection: The lead of the red test probe shall be connected to the jack marked with the "+" symbol, and the black test probe to the jack marked with the "−" or "*" symbol. Some multimeters are equipped with dedicated jacks for special measurements. When measuring such special quantities, reconnect the red test probe to the corresponding dedicated jack while keeping the black test probe unchanged.
(2) Measurement function selection: Turn the selector switch to the required position according to the object to be measured. Some analog multimeters have two selector knobs on the panel, which need to be coordinated to complete the measurement. Great care must be taken when selecting the function; carelessness may damage the meter. Particularly when measuring voltage, mistakenly selecting the current or resistance gear can cause serious damage or even burnout of the meter movement.
(3) Range selection: Select a range based on the estimated value of the measured quantity, and the selected range shall be greater than the measured value. When measuring current and voltage, the range should be chosen so that the pointer works in the region above 2/3 of the full scale to ensure measurement accuracy. When measuring resistance with a multimeter, the pointer should preferably fall between 0.1 and 10 times the central scale value. If the approximate range of the measured quantity cannot be estimated before measurement, first turn the selector switch to the maximum range for a preliminary test, and then select an appropriate range for formal measurement.
(4) Correct reading: The dial of a multimeter has multiple scales, each marked with symbols for the corresponding measured quantity. Read the value indicated by the pointer on the corresponding scale according to the measurement type and selected range. In addition, keep your line of sight perpendicular to the dial when reading. For analog multimeters with a mirror scale, take the reading only after the pointer overlaps with its reflection in the mirror.
