Precautions of Using Ohm Meters

Precautions of Using Ohm Meters Points : Precautions of Using Ohm Meters, Precautions while Measuring Resistance by Ohmmeter, How to take the read inns of Ohmmeter, Precautions while Measuring Resistance by Ohmmeter

1. If there is little or no pointer movement from the left side of the scale, reset the selector switch to a higher range in an effort to get greater deflection. The best readability on an ohmmeter range is between midscale and zero.
2. Short the leads by touching the leads together, the pointer should read zero at the right hand end of the Ω scale, if it does not use the ohm adjust knob to line up the pointer with zero. (If pointer can not be brought to zero, replace battery).
3. Take reading on the: ohm” scale and multiply it by the multiplication factor inducted by the selector switch.
4. Disconnect all power from resistance to be measured before applying the test leads.
5. Plug the black test lead into the (-) jack and the red test lead into the (+) jack.
6. Do not check resistance in a circuit while power is “ON” or before circuit capacitors are discharged.
7. Set the selector switch to the appropriate ohm range.
8. Connect the test leads across the resistance to be measured.
9. When switching ranges, readjust pointer to “0” Ω each time.

Scale Reading on Different Range Settings Following fig. (a) and (b) show the shape of scales of series and shunt type ohmmeters.

How to take the readings of Ohmmeter Following procedural steps are taken for resistance measurement with ohm meter.

1. Short test leads (probs) together and adjust Ω adjustment knob to set the pointer exactly on the zero ohm. This procedure is called zero ohm adjustment. If zero ohm adjustment can not be made, replace the battery.
2. Connect the test probs to the circuit whose resistance is being measured.
3. Obtain the measured value by multiplying the, Ω, K Ω or M Ω reading by the range factor.
4. Read the pointer reading on the ohm scale.
5. Set range switch to desired Ω range.

Precaution When the resistance measurement has been completed, set the range selector to one of the current or voltage ranges. Otherwise the battery will be drained.