In order to measure the electrical resistance of a component of an electrical circuit, it is necessary that the circuit is OFF.
The instrument used to measure the electrical resistance is called OHMIMETER, the multimeters also have scales used for measuring electrical resistance.
We must initiate the measurement by selecting the largest scale of the instrument and lowering the graduation through the selector switch until a measurement with the proper accuracy is made, connecting the instrument tips always in PARALLEL with the component.
When performing this procedure if the resistance to be measured is very low the instrument will indicate in its display, if digital, the value "000", it is then necessary to continue lowering the scale until it indicates the actual value of the resistance of the component.
If the value of the electric resistance to be measured is greater than the selected scale, the instrument will show "I" to the left of the display, indicating that for the selected scale the resistance value is "infinite", the selected scale must be increased until to obtain the electrical resistance value with the highest precision offered by the instrument. The symbol used to indicate the resistance scale on an ohmmeter or multimeter is the Greek letter Ω (Omega).
