소개
A multimeter helps you prove what’s actually wrong in an appliance before you spend money on parts. This guide walks you through the four most useful functions for appliance work—continuity, resistance, AC voltage, and amperage—using a basic digital meter (like an AstroAI unit) and a clamp meter (like the Klein CL120) as examples.
필요한 것
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1 단계 Follow basic electrical safety rules
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Unplug the appliance or shut off the breaker before doing continuity or resistance tests.
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2 단계 Understand what the meter is measuring
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Use a multimeter to check whether an electrical signal can travel between two points.
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Set the dial to the function you want, then place one probe on each point you want to compare.
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3 단계 Use continuity mode for quick pass fail checks
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Turn the dial to continuity, which is often shown as a sound-wave or Wi‑Fi-like symbol.
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Touch the probe tips together to confirm the meter beeps and reacts on the display.
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Touch one probe to each end of the part or wire you’re checking to see whether it can pass a signal from point A to point B.
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4 단계 Test a thermal fuse with continuity
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Set the meter to continuity to test a thermal fuse.
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Place the probes on the fuse’s metal terminals to check for a signal.
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5 단계 Isolate a component before testing it
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Remove at least one spade terminal from the component you’re testing so the reading doesn’t backfeed through the rest of the appliance.
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Touch the probes only to the two points that belong to the component you want to measure.
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6 단계 Interpret OL and typical heater readings
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Watch for an OL reading, which indicates an open line and no connection between the probes.
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Check heating element terminals with the probes to get a resistance value instead of OL when the element is intact.
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7 단계 Check a heating element for a dangerous short to ground
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Set the meter to continuity and place one probe on a heater spade terminal.
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Place the other probe on the heater’s metal cabinet or chassis to see whether the heater is electrically connected to the cabinet.
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8 단계 Use resistance mode for coils and motors
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Use resistance when a component needs both continuity and a specific ohms value to confirm the coil is wound properly.
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Measure across the two motor or coil leads and compare the reading to the expected specification for the part or model.
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9 단계 Test a variable resistance sensor
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Measure resistance on a sensor by placing the probes on its two terminals, using the rear metal connections when needed.
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Consider a sensor suspect if it’s off spec, because it can make the appliance “think” it’s hotter or colder than it really is.
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10 단계 Confirm a thermistor responds to warmth
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Measure resistance across the thermistor’s terminals and note the starting value, which can be around 10,000 ohms in the example.
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Warm the sensing area with a finger and watch the resistance drop as it heats up.
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Remove your finger and watch the resistance climb again as the sensor cools.
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11 단계 Measure live AC voltage at an appliance power connection
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Turn the dial to AC voltage, which is shown with a squiggly line, not the straight line and dots used for DC voltage on circuit boards.
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12 단계 Use a clamp meter to measure amperage on a single wire
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Turn the clamp meter to the A setting and use the lowest appliance range, usually between 2 and 20 amps.
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Turn the appliance function on and read the current draw to see what it’s actually consuming.
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Separate the wires so only a single conductor is inside the clamp jaw.
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13 단계 Diagnose common appliance problems with amperage
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Use amperage on a gas stove igniter circuit to confirm whether it’s drawing enough current to open the safety valve.
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Use amperage on a refrigerator compressor wire to see how much work the compressor motor is doing.
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Use continuity for simple pass-or-fail parts like fuses and for checking wiring paths, use resistance to confirm coils and sensors are in spec, use AC voltage to verify power is actually present, and use a clamp meter to see what current a load is really drawing. Recheck probe contact if readings seem odd, and isolate components by removing at least one terminal whenever possible.
