What is the reason why the resistance value of the 5-color ring resistor cannot be measured when measured with a multimeter?
First, you need to determine the nominal resistance of your resistor. You need to know that common resistors may range from a few tenths of ohms to tens of megaohms (one megabyte equals one million ohms). First determine the nominal resistance value, and then select the range of the multimeter. If it is a digital meter, if the resistance exceeds the range, there will be no reading (displayed as infinity). If the analog multimeter exceeds the range too much, the pointer cannot swing, or only moves slightly. Only when the range is greater than the resistance of the resistor being measured, the reading can be obtained.
Use your multimeter to measure the resistance. It is best to select the high-resistance range first and then select the position from the high-resistance range to the low-resistance range to improve the accuracy of resistance readings. Some high-resistance products have low resistance values ranging from several hundred K to several thousand K, and the low-resistance reading cannot show the resistance value. Some resistors can be used. If the resistance value cannot be determined at the high resistance level, the resistor cannot be used. for reference.
I used a digital multimeter, and the resistance cannot be measured in the on-off mode, at least not accurately. If you use the 2M ohm setting and there is no response when measuring, it means that the resistor is open circuit, that is, it is broken. Replace it with a new one!
The five-color ring resistor cannot measure the resistance value of the resistor. There are only two possibilities. One is that the meter is bad. But the resistor is open circuit (infinity)!
Increased resistance, unstable resistance, and open circuit resistance are common faults of resistors.
Digital multimeter to test the quality of capacitors
When using a digital multimeter, turn it to the capacitance setting and use the capacitance setting to measure, and turn it to the 200uf setting. Only by using this range can you accurately measure the data. Because it is not an electrolytic capacitor, there is no distinction between positive and negative poles. When measuring, the digital display starts with a small value. The numbers begin to increase gradually. Change the capacitance test pen and re-measure the reading of the digital meter. It is normal to gradually decrease from a high value to a small value. Otherwise, when the direct reading stops at a certain value, it is a sign of damage. Then use a 200 ohm resistor. If the measurement level is zero or the resistance value is very small, it is a breakdown state. When using the capacitance level, please follow the test lead connection method in the following picture for normal use and measurement.
Use the capacitance setting of the multimeter to test the capacity and see how big the error is with the nominal capacity? Within 20% is considered normal.
Then use the resistance setting to measure the resistance of the capacitor. The time will be longer because there is a charging process, usually within 10-30 seconds. When the data is stable, it can be regarded as the measurement is completed. The result should be infinite, otherwise the capacitor is leaking.
However, this test is incomplete because the voltage of the multimeter is too low and cannot measure the leakage status of the capacitor under high voltage. Many capacitors are damaged due to high-voltage breakdown and leakage.
