Modern digital multimeters come in all shapes and sizes. The following is a guide on the basic operation for an autoranging meter. If your meter requires you to manually set a measurement range, you may need to refer to the manual that came with the meter to determine the proper setting and reading. Let’s take a look at the features of a typical modern meter (it is a general diagram designed for illustrative purposes only that does not represent any particular meter).
- 1) This is the screen where your results will be displayed.
- 2) Off position. Keep your meter turned off when not in use to preserve battery life.
- 3) AC voltage. You will use this setting to perform tests requiring an Alternating Current measurement.
- 4) DC Voltage. You will use this setting for tests requiring a Direct Current measurement.
- 5) Resistance (Ohm): This setting is used for any test calling for a resistance reading, which is measured in the base unit Ohm.
- 6) Continuity: This setting will tell you if there is an electrical path (continuity) between two points, does not yield a specific number.
- 7) Diode: This is a special setting on the meter in order to accurately measure diodes.
- 8) Milliamps: This setting will measure milliamps up to the meter specific maximum mA reading (mA =1/1000th of an amp)
- 9) Amperage: Measures amperage up to the meter specific maximum.
Multimeter Usage Quick Tips
- The meter shown above represents a typical auto-ranging meter in which the meter will automatically select the appropriate range (readings will appear in the display along with the measurement unit). If using a manual-ranging meter you will need to set it to the correct range first. If unsure refer to the meter specific operation manual or contact the manufacturer of your meter.
- Elements of electricity are measured via the metric system, so make sure you have a solid understanding of metric prefixes. For instance, 500 ohms = 0.500 kilo-ohms (k).
- Keep your meter leads and test points clean. Oxidation, grease or dirt of any kind may result in erroneous readings. If getting unusual readings, clean your meter leads, set the meter to Ω measurement, and touch the two leads together. Any significant resistance between the two indicates a problem with either the leads or the meter.
- CAUTION: When taking measurements in a live circuit never allow the metal part of the probes to contact your body, (fingers, etc.), as a potentially lethal amount of electricity may pass through your body.
- To prevent erroneous readings when bench or static testing (non power) be sure to hold the test probes by the insulated plastic body only or use “alligator clip” style probes.
- If readings are not as expected try testing something of a known value to confirm the meter is working properly or if you have more than one meter verify with a second meter.
- Be sure the batteries are not weak and fuses are good in the meter as this may also result in erroneous readings.