Resistance is an important parameter value of crystal products. If you want to test the resistance of a crystal, the fastest and most convenient way is to use a multimeter to measure it. As long as you use the two ends of the multimeter to contact the resistance, you can quickly test its resistance. What is the specific method? What is the principle of the multimeter to measure the resistance?

    How to measure resistance with multimeter:

    1. The multimeter we use, whether it is measuring voltage or current, resistance, is a common meter head. When we need to measure the resistance, we must first adjust to the ohm range. Generally have: x1, x10, x100, x1000 several gears.

    2. If the pointer of the meter or the reading is not zero when the arm of the digital multimeter is short-circuited before the measurement, there will be zero error in the reading. If we find before testing that there is no return to zero, we must first set it to zero, as follows:

    1) The multimeter has two test leads, one red test lead and one black test lead. The red test lead is inserted into the jack marked with a "+" sign, and the black test lead is inserted into the jack marked with a "-" sign. When adjusting the mechanical zero position, first disconnect the two test leads. If the hand does not stop at the zero position at the left end of the dial, use a screwdriver to turn the set screw O under the dial and adjust the pointer to the mechanical zero position through the coil spring in the table.

    2) Touch the two test leads, that is, short-circuit, and the resistance between the two test leads is zero. At this time, the meter hand should stop at the "0Ω" resistance value at the right end of the dial. At this time, the current is maximum. However, because the battery has been used, the pointer is generally not at the zero position of the resistance value when the test lead is short-circuited. At this time, the zero adjustment knob Q can be turned to make the pointer point at zero ohm.

    3. Select the magnification

    Using a multimeter to measure the resistance, in order to facilitate accurate readings, the pointer should be in the middle of the dial as much as possible, so it is necessary to properly select the magnification stop. For example, when measuring the resistance of R1 = 50Ω, you should choose "× 1" to make the hand deflect near the middle of the dial. If "× 10" is selected, the dial reading will be enlarged by 10 times, which will make the hand to the right side of the dial and the reading will be difficult to be accurate. In general, you can choose the appropriate magnification in this way, divide the magnitude of the RX value of the resistance to be measured by 10, and the resulting quotient is the magnification you should choose. For example, measuring the resistance of RX = 510kΩ, the order of magnitude of RX is 100k, (RX = 5.1 × 100k), so it is better to choose “× 10k” magnification. If the universal multimeter does not have a × 10k ratio block, you can choose the closest block.

    If you don't know the resistance value in advance, you can try to select the magnification scale. When the hand can be pointed near the middle of the dial, the magnification scale is more suitable. Now digital multimeters no longer need to choose the magnification. In it There is only one ohm range on the panel, so we only need to adjust the ohm range when testing. It directly shows the resistance value of the resistor.