According to AllAboutCircuits.com, electrical resistance, measured in Ohms, is essentially electrical friction encountered by electrons as they move through a conductor. Ohms are typically symbolized by the Greek letter omega. The easiest way to measure resistance in a circuit is to use an ohmmeter or a multimeter. Most electricians will use a multimeter as it allows them to measure different things with the same instrument. If you are planning on doing any electrical work in your house it's a good idea to have solid grasp on using an ohmmeter.
Things You'll Need
An Ohmmeter Or Multimeter
Red And Black Electrical Leads
Video of the Day
Instructions
Step 1
Select the ohms setting on your multimeter and set it to the highest resistance range available. Some models will auto-set the range for you. If you are using an ohmmeter, set it to the highest resistance range.
Video of the Day
Step 2
Plug the black lead into the socket labeled "Com" on your meter. Plug the red lead into the socket marked by the Greek letter omega.
Step 3
Touch the ends of the two leads together. If your meter is properly functioning the display should read 0.0. It may read a slight bit higher, as the leads themselves have resistance, but if it reads over 0.3, you may have a defective meter.
Step 4
Touch each the end of each lead to the end of the wire you wish to measure. Touch the leads to the wire at the same time to complete a circuit. The meter should display a reading of the resistance in ohms of the wire.
Step 5
Make a note of the reading and adjust power as necessary to ensure proper functionality of the circuit.
Tip
Resistance is not usually measured across a complete circuit, rather it should be measured across each potential component of the circuit.
Warning
Never measure resistance across a live, powered circuit. Doing so may damage your meter and even cause personal injury.