How to Use an Analog Ohm Meter

You can learn to use an analog ohmmeter in a few easy steps

While an analog multimeter has the same basic function as a digital one, you'll find differences in its use. To read resistance, you must first set the meter for the right range and zero it every time you select a new range. Taking a reading with a needle on a dial face is also different from reading numbers from a digital display. Accurate readings take longer, but you can take the same kinds of measurements you can with a digital meter.

Things You'll Need

• Analog ohm meter
• Resistor assortment

Instructions

1. Select a resistor from your assortment.

2. Select a suitable range on the ohmmeter. For example, if the resistor's value is 5600 ohms, select the R x 1,000 ohm range.

3. Touch the ohmmeter's probe leads together. Zero the meter by turning the resistance zero adjustment knob until the needle points to zero, at the right extreme of the meter scale. If it won't adjust to zero, replace the meter's battery with a fresh one.

4. Touch the ohmmeter's probe leads to the resistor so the black probe lead is on one side of the resistor, and the red probe is on the other. You may hold one connection with your fingers, but make sure you're not touching the metal tips of both probes with your hands. The resistance of your hands and body will interfere with the accuracy of the reading.

5. Read the value on the scale. Note that this is most easily done if the resistor reads on the right half of the scale. As the numbers increase on the left side, they're bunched up logarithmically, making readings there more difficult.

6. Interpret the reading by taking the value you see on the meter and multiplying it by the resistance scale switch setting. For example, if you see a meter reading of 17, and the scale switch is set to R x 100, the actual resistance measurement is 17 x 100 or 1700 ohms.

Tips & Warnings

• Read the meter directly facing it instead of off to one side, if possible. The needle is a slight distance above the scale, so if you read it from an angle, the reading may suffer from parallax error.

• If the logarithmic scaling at the left side of the meter makes the reading difficult, try switching to a larger resistance scale.

• Anytime you change scales, you'll have to zero the meter again.

References

• All About Circuits: Basic Concepts and Test Equipment
• Marine Institute of Memorial University: Resistor Code and the Ohmmeter