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.
Odpor sa musí merať pri vypnutom obvode, inak dôjde k poškodeniu merača alebo dosky plošných spojov. Niektoré digitálne multimetre poskytujú funkciu ochrany, keď je napäťový signál omylom pripojený v odporovom režime. Rôzne modely DMM majú rôzne ochranné schopnosti.
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.
Ak digitálny multimeter dodáva menej ako 0,6 V jednosmerné napätie na meranie odporu, môže merať hodnotu odporu dosky plošných spojov izolovanej diódou alebo polovodičom. Dá sa otestovať bez odstránenia odporu.
