• How to test a resistor

    Resistors add a load to a circuit and drop the current flow. The amount of resistance applied by each resistor will effect the voltage and amperage found in the circuit.



    Most resistors are small, long, cylinder shaped pieces, with a metal wire protruding out of each end that is soldered onto a printed circuit board. Resistors can be run in series or parallel into the circuit, and depending on how it is inserted, will determine how much it changes current and voltage.

    Resistors are labeled with distinct colored bands that indicate it's resistance value. Click here to see view a resistor color coding chart.

    Resistor Test

    Step 1- Unsolder the resistor.

    Unsolder one end of the resistor from the circuit board. If the resistor is already separate from a circuit board, proceed to step 2.

    Step 2- Set up the multimeter.

    Set the multimeter to the Ohms resistance setting. Use the resistance range that will best suit the resistor's specific value.

    Step 3- Test resistance across the resistor.

    Hold the red meter probe to one lead of the resistor, and touch the black meter probe to the opposite lead.

    Step 4- Review the test results.

    Read the display on the multimeter to see if it matches the indicated value of the resistor. If it matches, then the resistor is good. If the measured value is different, then the resistor is defective.

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