How to Measure resistance of digital multimter Professional?
Resistance is measured at the electrical barrier. Resistance values vary widely, from a few milliohms (mΩ) for contact resistance to billions of ohms for insulation resistance. Many DMMs measure resistances as small as 0.1 ohms, and some measurements can be as high as 300 megohms (300,000,000ohms). If the resistance is extremely large, the Fluke multimeter will display "OL", indicating that the measured resistance exceeds the range. When measuring an open circuit, "OL" is displayed.
Motståndet måste mätas med strömkretsen avstängd, annars uppstår skador på mätaren eller kretskortet. Vissa digitala multimetrar ger en funktion av skydd när en spänningssignal av misstag ansluts i motståndsläge. Olika modeller av DMM har olika skyddsmöjligheter.
For accurate measurements of low resistance, the resistance of the measuring lead must be subtracted from the measured value. Typical test lead resistance values are between {{0}}.2Ω and 0.5Ω. If the resistance of the test leads is greater than 1Ω, the test leads should be replaced.
Om den digitala multimetern levererar mindre än 0.6V DC-spänning för att mäta resistansen, kan den mäta resistansvärdet på kretskortet som är isolerat av dioden eller halvledaren. Det kan testas utan att ta bort motståndet.
