Twelve Key Points for Multimeter Operation Precautions
① Before use, check whether the pointer rests at zero. If not, adjust the pointer zero‑adjuster first.
② Set the selector switch to the corresponding position according to the type of measured quantity. Special attention shall be paid: when measuring voltage, do not set the selector switch to current or resistance gear; otherwise the multimeter may be burnt out.
③ When measuring DC current or DC voltage, insert the red test lead into the jack marked red or "+", and connect its other end to the positive pole of the measured object. Insert the black test lead into the jack marked black or "‑", and connect its other end to the negative pole of the measured object.
④ For current measurement, connect the multimeter in series with the circuit under test. For voltage measurement, connect the multimeter in parallel with the circuit under test.
⑤ When measuring voltage or current, accurate readings are obtained when the pointer deflects within 1/2 ~ 2/3 of full‑scale range. If the magnitude of the measured quantity is unknown in advance, select the maximum range of this category for preliminary measurement to avoid damage caused by insufficient range, then switch to a proper range to reduce measurement error.
⑥ There are multiple scales on the multimeter dial for different measurement types. During measurement, read values from the corresponding scale according to the function and range selected by the selector switch, and pay attention to the multiplier relationship between the selected range and scale readings.
⑦ Select an appropriate multiplier gear for resistance measurement. The resistance scale reads backward with non‑uniform graduations: graduations get denser toward the left and measurement accuracy degrades accordingly. Therefore, adjust the pointer to the middle‑to‑right section of the resistance scale, preferably near the scale midpoint.
⑧ Perform zero‑ohm adjustment before resistance measurement: short‑circuit the red and black test leads, and turn the ohm‑zero adjustment knob until the pointer points to the "0" mark on the resistance scale. Re‑zero‑adjustment is required after each multiplier‑gear change before taking measurements. Replace the battery if the pointer cannot reach zero.
⑨ When measuring resistance, at least one terminal of the measured resistor shall be disconnected from the circuit, and power supply shall be cut off before measurement.
⑩ Do not turn the selector switch with power applied when measuring high‑voltage or large‑current signals to ensure personal safety.
⑪ Upon completion of each measurement, set the selector switch to the highest AC voltage range or OFF position, to prevent damage from misuse by other personnel.
⑫ Remove the internal battery if the multimeter will not be used for a long time, to prevent battery corrosion and damage to other components.
