The use of ohmmeters is somewhat more involved. Most importantly when measuring resistance the circuit power must be switched off, power is derived from within the instrument. Secondly, great care must be taken to ensure there are no parallel paths that would affect the measurement. This is generally best confirmed by removing the component or device, or by disconnecting one end of it from the circuit concerned.
Thirdly, it is essential that an analogue meter is zeroed before it is used.
To measure resistance, the meter is simply connected across the component or device to be measured. The polarity of the leads is not important unless semiconductor type devices are present. (this will be discussed in a later module).
When making resistance measurement, care must be taken to ensure the correct range is used. It is easy to mistake a low resistance value for a zero reading or short circuit.