How to judge the quality of a general capacitor using a digital multimeter
If there is no capacitance range, use a resistance range to measure and briefly observe the charging and discharging situation of the capacitor.
1. Estimating the capacity of microwave level capacitors: It can be determined based on experience or by referring to standard capacitors of the same capacity, and the maximum amplitude of pointer oscillation.
2. Estimating the capacity of a picosecond capacitor: R should be used × 10k Ω range, but can only measure capacitance above 1000pF. For capacitors of 1000pF or slightly larger, as long as the watch needle swings slightly, the capacity is considered sufficient.
3. Test for leakage of capacitance: For capacitors above 1000 microf, R can be used first × Quickly charge it at 10 Ω level and preliminarily estimate the capacitance capacity, then change it to R × Continue measuring at 1k Ω level for a while, and at this point, the pointer should not return, but should stop at or very close to ∞, otherwise there will be leakage.
4. Turn the function switch to the 20uF or 200uF position, place the probes in the middle two holes, and measure the capacitance at both poles. At this point, the capacity will be displayed. If it is a used capacitor, it must be discharged before measurement.
Extended Information:
Digital multimeter resolution:
Resolution refers to the quality of a meter's measurement results. By understanding the resolution of a table, you can determine whether small changes in the measured signal can be seen. For example, if the resolution of a digital multimeter is 1mV within the 4V range, then when measuring a 1V signal, you can see a small change of 1mV (1/1000 volts)
If you want to measure a length less than 1/4 inch (or 1 millimeter), you will definitely not use a ruler with the smallest unit of inches (or centimeters). If the temperature is 98.6 ° F, measuring with a thermometer with only integer markers is not useful. You need a thermometer with a resolution of 0.1 ° F.
Digits and words are used to describe the resolution of a table. Numeric multimeters are classified based on the number of digits and words they can display.
A 3 and a half digit table can display three full digit digits from 0 to 9, and one half digit (only 1 or no display). A 3 and a half bit digital table can achieve a resolution of 1999 words. A 4 and a half bit digital table can achieve a resolution of 19999 words.
The resolution of using words to describe a digital table is better than using bits, and the resolution of a 3 and a half bit digital table has been improved to 3200 or 4000 words.
The 3200 word digital table provides better resolution for certain measurements. For example, a 1999 word meter cannot display 0.1V when measuring a voltage greater than 200V. The 3200 word digital meter can still display 0.1V when measuring a voltage of 320 volts. When the measured voltage is above 320V and the resolution is to reach 0.1V, a more expensive 20000 word digital meter is required.
