The ohm range of a multimeter can measure the resistance of a conductor. The ohmic range is represented by "Ω" and is divided into R × 1. R × 10. R × 100 and R × 1K fourth gear. Some multimeters also have R × 10k gear. To measure resistance using the ohm range of a multimeter, in addition to the requirements that should be met before use, the following steps should also be followed.

1. Set the selector switch to R × At position 100, short circuit the two probes to adjust the zero position adjustment knob of the ohm range, so that the probe points towards the zero position at the right end of the resistance scale line. If the pointer cannot be adjusted to zero, it indicates that the battery voltage in the meter is insufficient and the battery should be replaced.

2. Use two probes to contact the two pins of the measured resistance for measurement. Correctly read the value of the resistance indicated by the pointer, and then multiply it by the magnification (R × 100 gears should be multiplied by 100, R × 1k gear should be multiplied by 1000...). It is the resistance value of the measured resistance.

3. To ensure accurate measurement, the pointer should be positioned near the center of the scale line during measurement. If the pointer deviation angle is small, R should be used instead × 1k gear, if the pointer deviation angle is large, R should be used instead × 1O or R gear × 1st gear. After each gear shift, adjust the zero adjustment knob of the Ohm gear again and then measure again.

The principle of measuring resistance with a multimeter is the single coil ohmmeter method. Due to the different resistance values connected to each gear in the resistance range, there is a tenfold increase in resistance values, such as × 1, × 10, × 100, × 1000, × 10k. After short circuiting the terminals, the internal resistance in the battery is equal to the internal resistance in the meter head × The resistance of the first gear is connected in series, and when the battery voltage remains constant, the current flowing through the meter coil corresponds exactly to the ohmic zero position, that is, the terminal voltage of the meter coil corresponding to the zero position is constant. If the resistance values of each gear are changed, the terminal voltage of the meter head will change, causing the current flowing through the meter head to also change accordingly, and the meter needle will no longer refer to the ohmic zero position. For example, changing the resistance range from R × When the first gear is gradually changed to a high gear, the voltage on the meter head also decreases gradually, and the current decreases gradually, causing the pointer to deviate less than the zero ohm position, which will cause significant measurement errors. So it is necessary to adjust the zero adjustment knob to maintain the current of the meter coil unchanged, and to reset the pointer to the zero position of the ohm to ensure the accuracy of each gear during measurement.