[header] How to measure resistance [title] Choose the item whose resistance you wish to measure. [step] For the most accurate measurement, test the resistance of a component individually. Remove the component from the circuit or test it before you install it. 
Testing the component while still in the circuit can cause inaccurate readings from other components. [substeps] If you are testing a circuit or even just removing a component, be sure that all power to the circuit is turned off before proceeding.