Measuring Resistance

Measuring Resistance:

Resistance is measured with a Ohmeter. If you are using a multimeter, you will need to switch the measurement setting to Ohms or .

To measure resistance, the component may need to be taken out of circuit if there is a possibility that the resistance of other components in the circuit may affect the reading.


  • You must disconnect the power to the circuit before measuring Resistance. The meter will supply its own power to get the reading. NOTE: Low batteries on your multimeter can affect the reading!
Schematic Symbol  Description



No harm should come to your meter or component if you are in the wrong resistance range. You will either get an infinite resistance reading (or OL on a digital meter) if the range is too high, or a Zero reading if the range is too low. Select a different resistance range to get a more specific result.

As resistance readings do not require the components to be in circuit, it can be a good way to check their values, before connecting them to the circuit. This is a good way of double checking the values of resistors before connecting them to your circuit – The colour bands that identify them can sometimes be vague and confusing if you are not familiar with them.