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.

IMPORTANT:

  • 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
 Symbol-Ohmmeter

Ohmmeter

Fig9-Ohmmeter-Connection-Schematic

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.