How to measure 400 microfarad capaciteit met met pointer multimeter
Condensatoren zijn een van de meest vaak gebruikt elektronisch componenten. De vorm en circuit symbool van de condensator zijn getoond in de figuur. De gemeenschappelijke tekst symbool voor condensatoren is "C". De condensator is hoofdzakelijk samengesteld van metaal elektroden, diëlektrica lagen en elektrode leads, en de twee elektroden zijn geïsoleerd van elk andere. Daarom, it heeft de basis prestaties van "blocking DC en communicatie met AC".
Some digital multimeters have the function of measuring capacitance, and their ranges are divided into five levels: 2000p, 20n, 200n, 2μ and 20μ. When measuring, the two pins of the discharged capacitor can be directly inserted into the Cx jack on the panel, and the displayed data can be read after selecting an appropriate range. 2000p file is suitable for measuring capacitance less than 2000pF; 20n file is suitable for measuring capacitance between 2000pF and 20nF; 200n file is suitable for measuring capacitance between 20nF and 200nF; 2μ file is suitable for measuring capacitance between 200nF and 2μF Capacitance; 20μ range, suitable for measuring capacitance between 2μF and 20μF.
Ervaring heeft bewezen dat sommige typen van digital multimeters (zoals als DT890B plus ) hebben grote fouten wanneer meten kleine-capaciteit condensatoren onder 50pF, en daar is bijna geen referentie waarde voor meten capaciteit onder 20pF. At this time, de serie methode kan be gebruikt om meten kleine-waarde capaciteit. De methode is: eerste vind a condensator van ongeveer 220pF, measure its actual capacity C1 with a digital multimeter, and then connect the small capacitor to be tested in parallel to measure its total capacity C2, then the difference between the two (C1-}C2) is The capacity of the small capacitor to be tested. It is very accurate to measure the small capacity capacity of {{10}% 7dpF door dit methode.
Detection met weerstand bestand
Practice has proved that the charging process of the capacitor can also be observed by using a digital multimeter, which actually reflects the change of the charging voltage with discrete digital quantities. Assuming that the measurement rate of the digital multimeter is n times/second, when observing the charging process of the capacitor, n readings that are independent of each other and increase sequentially can be seen every second. According to this display feature of the digital multimeter, it is possible to detect whether the capacitor is good or bad and estimate the capacitance. The following is a method to detect capacitors using the resistance range of a digital multimeter, which is of great practical value for instruments that do not have a capacitance range. This method is suitable for measuring large-capacity capacitors ranging from 0.1 μF to several thousand microfarads.
1. Meting werking methode
Turn the digital multimeter to the appropriate resistance level, and the red test lead and the black test lead respectively touch the two poles of the capacitor Cx under test. At this time, the displayed value will geleidelijk toename van "000" until the overflow symbol "1" is display. Als "000" is always displayed, it betekent dat de condensator is intern kortgesloten; if it is always displayed as overloop, it kan be dat de internal electrode of de condensator is open, or the selected resistance file may not be suitable. Wanneer controleren de elektrolytisch condensator, it moet worden genoteerd dat de rode test lood (positief geladen) is verbonden met de positieve pool van de condensator, en de zwart test lood is verbonden met de negatieve pool van de condensator.
2. Meten principe
The measurement principle of meting condensatoren met weerstand files is getoond in Figuur {{{0}}(b). During the measurement, the positive power supply charges the measured capacitor Cx through the standard resistance R0. At the moment of charging, because Vc=0, "000" is displayed. As Vc increases geleidelijk, the displayed waarde stijgt navenant. When Vc {{4% 7d}VR, de meter starts aan display de overloop symbool "1". Opladen tijd t is de tijd vereist voor de display waarde naar verandering van "000" to overflow, en this periode van tijd kan be gemeten door a kwarts horloge.
3. Gemeten data voor schatting capaciteit gebruik a digital multimeter
Wanneer gebruik a digital multimeter tot schatting de capaciteit van a condensator van 0.1 μF to several thousand microfarads, you can select the resistance range volgens aan Tabel 5-1}. The range of measurable capacitance and the corresponding charging time are given in the table. The data listed in the table is also of reference value for other models of digital multimeters. the
The principle of selecting the range of the resistance file is: when the capacitance is small, the high resistance file should be selected, and when the capacitance is large, the low resistance file should be selected. Als u gebruik a hoge weerstand bestand tot schatting a grote capaciteit condensator, omdat het opladen proces is zeer langzaam, de meting tijd zal laatste voor a lange tijd; als u gebruik a lage-weerstand bestand aan check a kleine-capaciteit condensator, omdat de opladen tijd is zeer kort, de meter zal altijd display overloop, en de verandering proces kanniet gezien worden .
How to judge de kwaliteit van air conditioner condensator
Check met a digital multimeter, set the digital multimeter to the appropriate resistance level, and the red test lead and black test lead respectively touch the two poles of the capacitor under test. At this time, the displayed value will geleidelijk toename from 000 tot the overflow symbol "1" is displayed. If 000 is always displayed, it means that the capacitor is shorted internally. Als overloop is altijd weergegeven, it may be an open circuit tussen de elektroden binnen de condensator, of de geselecteerde weerstand bestand kan be ongepast.
In order to see the charging process of the capacitor on the display screen, different resistance levels should be selected for capacitors with different capacities. The principle of selecting the resistance file is: when the capacitor is large, the low resistance file should be selected; when the capacitor capacity is small, the high resistance file should be selected. If you use a low-resistance file to check a small-capacity capacitor, because the charging time is very short, it will always display overflow, and the change process cannot be seen, so it is easy to misjudge that the capacitor is open. If a high-resistance file is used to check a large-capacity capacitor, the measurement time needs to be relatively long due to the slow charging process. For capacitors above 0.1~1000uF, the resistance range can be selected according to the table (the charging time in the table refers to the time required for the display range to change from 000 to overflow).
