Check the function and range before measuring
Always verify the selected measurement function and range switch before using the probes. For safety, make this a habit and do not measure without checking.
Do not change the range during measurement; switch to off after measuring
Do not move the selector knob while measuring, especially when measuring high voltage (for example 220 V) or large currents (for example 0.5 A), to avoid arcing and damaging the switch contacts. After finishing a measurement, set the range selector to the off position.
Keep the dial level and align your line of sight
For analog multimeters, hold the meter level and read the pointer with your eye directly aligned with it to avoid parallax error.
Choose an appropriate range; aim for about two-thirds full-scale on analog meters
If the magnitude of the quantity is unknown, start with a higher range. For analog meters, reduce the range stepwise until the pointer deflects to roughly two-thirds of the full scale.
Do not measure resistance on live circuits; discharge capacitors before measuring
Never measure resistance when the circuit under test is energized. When checking large capacitors, short them to discharge before measuring.
Zero the meter for resistance measurements; re-zero after changing range
When measuring resistance, set the selector to the resistance range, short the two probes, and adjust the "Ω" zero potentiometer until the pointer reads zero ohms before measuring. Readjust the ohm zero each time the resistance range is changed.
Remember probe polarities; the black probe connects to the internal battery positive on resistance range
The red probe is positive and the black probe is negative. On the resistance range, however, the black probe is connected to the internal battery positive terminal.
Measure current in series, measure voltage in parallel
When measuring current, insert the multimeter in series with the circuit under test. When measuring voltage, connect the multimeter in parallel across the two points of the circuit under test.
Do not reverse polarities; use single-hand operation habitually
Pay particular attention to not reversing the red and black probes when measuring current and voltage, and develop the habit of one-handed operation for safety.
