Testing Resistors with a Multimeter

This experiment shows how to measure the resistance of a resistor using a digital multimeter.

Understanding how to test resistors is one of the most basic and useful skills in electronics. It helps you verify component values and troubleshoot circuits.

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Goal

Learn how to measure resistance using a multimeter and understand how resistors control current in electronic circuits.

What You Need

• Digital multimeter
• One or more resistors

Resistor Example

Measuring a resistor using a digital multimeter.

Steps

• Turn the multimeter dial to the resistance (Ω) mode.
• Hold the resistor by its body.
• Touch one multimeter probe to each lead of the resistor.
• Observe the resistance value displayed on the screen.
• Compare the measured value with the resistor color code.

What You Should Observe

The multimeter will display a resistance value in ohms (Ω), kilo-ohms (kΩ), or mega-ohms (MΩ) depending on the resistor.

The measured value should be close to the rated value of the resistor, although small variations are normal.

Why This Happens

A resistor limits the flow of electric current in a circuit.

When the multimeter measures resistance, it sends a very small test current through the resistor and calculates the resistance using Ohm’s law.

Try This

• Measure resistors with different values.
• Compare the multimeter reading with the resistor color bands.
• Test resistors from old electronic devices and see if their values match the markings.

Always measure resistance when the resistor is not connected to a powered circuit.