The Zero Ohms Adjusting Knob on the Multi Tester Tool

The VOM (Volt-Ohm Meter) is type of measuring equipment used for reading the three major properties of electricity which are the Voltage, Current and Resistance. 

This tool typically has a huge rotating knob on the middle part which allows you to select the type of electrical property that you would like to measure. 

At the bottom part are the two probes differentiated with Red and Black color. The Red probe denotes the positive terminal while Black for the negative terminal.

Now, you might be wondering about the other smaller rotating knob just above the huge selector which is labeled as Zero Ohm. 

This adjusting knob only concerns about resistance. It doesn’t have any effect when the primary selector is set for Voltage and Current.

When you are to read the resistance value of a certain resistor component, you have to hold the two probes with both of your hands. 

You have to make sure that your finger or some parts of your hands are not in-contact with the tip of the probe since it causes unstable result for the pointer. 

Gently attach the tips of the probes at the resistor’s terminals. You have nothing to worry about polarities since resistor components do not have positive and negative terminals.

Observe the meter scale and read the output of the value of your resistor. Write it down on a piece of paper for your reference on this next step.

You are to conduct the same procedure but before you start, rotate the Zero Ohms Adjusting knob setting the pointer on the meter scale perfectly at exactly zero (0) level or the first starting grid. 

When you are done then continue with the process of obtaining the result of the resistance value. This result is more accurate than the previous value that you have obtained.

For the DMM tool, the Zero Ohms Adjustment knob does not exist because the starting level is automatically adjusted by the equipment.