Make sure that contact between the test leads and circuit is good.Connect test leads across the component being tested. When finished, remove the leads in reverse order: red first, then black.ĥ.Then insert the red lead into the VΩ jack. First insert the black test lead into the COM jack.Ĥ. If the component is left in the circuit, the readings could be affected by other components in parallel with the component to be tested.ģ. Best results will be achieved if the component to be tested is removed from the circuit.Pressing the Range button allows a technician to manually set the range.When the leads are connected to a component, a digital multimeter automatically uses the Autorange mode to adjust to the best range.The MΩ symbol may appear in the display because the resistance of open (unattached) test leads is very high.The display should show OLΩ because, in Resistance mode, even before test leads are connected to a component, a digital multimeter automatically begins taking a resistance measurement.Turn digital multimeter dial to resistance, or ohms, which often shares a spot on the dial with one or more other test/measurement modes (continuity, capacitance or diode see illustration below).
If a circuit includes a capacitor, discharge the capacitor before taking any resistance reading.Ģ.Loads such as motors and solenoids decrease in resistance over time due to insulation breakdown and moisture. In general, the resistance of components used to control circuits (such as switches and relay contacts) starts out very low and increases over time due to factors such as wear and dirt. The higher the resistance, the lower the current flow, and vice versa. Why measure resistance? To determine the condition of a circuit or component.
0 kommentar(er)
