Question 40 CEL02 - Chief Engineer - Limited (Alt)

The Correct Answer is D **Explanation for Option D (OL ohms):** When a digital multimeter (DMM) is used to test resistance (set to ohms, $\Omega$) and the probes are connected across a component, the meter measures how easily current flows through that component. * A fuse is a safety device designed to have a very low resistance (approaching zero) when functional (good). * If the fuse is **blown** (open circuit), it means the conductive path is broken. Current cannot flow through the component. * The meter interprets a broken circuit as having infinite resistance. * Digital multimeters typically display **"OL"** (Over Limit or Open Loop) when the measured resistance exceeds the meter's maximum range or when an open circuit (infinite resistance) is detected. Since the meter is set to measure ohms, the display will show **"OL ohms"** (or just "OL" if the units are implied). **Why the other options are incorrect:** * **A) OL volts:** This reading would occur if the meter was set to measure voltage (Volts) and either the measured voltage exceeded the meter's range, or the probes were connected incorrectly for a high-voltage reading. Since the meter is set up to measure resistance (as implied by testing a passive component like a fuse for continuity), the units must be ohms. * **B) 0.001 ohms:** This value represents a very low resistance. This is the approximate reading you would see if the fuse were **good** (not blown) and conductive. A blown fuse has infinite resistance, not near zero. * **C) 470 ohms:** This is a measurable, finite resistance. Fuses are designed to have resistance approaching zero ohms when good. If the fuse were blown, the resistance would be infinite (OL). A reading of 470 ohms would indicate a resistive load, not a blown fuse or a good fuse.