What’s a Multimeter?
A multimeter, also known as a voltmeter, is a tool for measuring different electrical metrics. The three most common metrics include alternating current (AC) voltage, direct current (DC) voltage and resistance. Multimeters are particularly helpful for diagnosing issues with electrical systems. If something runs on electricity, a multimeter can measure its energy output, which can help you precisely identify electrical output errors.
The two main types of multimeters are digital and analog. Analog multimeters (AMM) use a physical pointer over a scale to relay readings. The electrical current passes through the multimeter’s coil that in turn magnetically moves its pointer. The pointer stops at measurements across several metric scales shown on the analog multimeter’s display, allowing one movement to provide multiple pieces of information about the electrical current’s strength across different metrics.
Digital multimeters (DMM) use a digital display to numerically inform users of electrical metrics, which are represented by discrete increments. The multimeters convert the input signal into voltage before intensifying the signal. This allows the multimeters to better process the signal, resulting in more precise measurements than those of analog multimeters.
However, despite their superior precision, digital multimeters aren’t always the preferred option. Digital readings tend to process more slowly than analog readings, which isn’t ideal for users who prioritize quick operations and/or are measuring constantly changing values.
How to Use a Multimeter
Before you try to use your multimeter, you need to understand its different parts. It’s important to take the time to understand this device before usage, since a lack of caution can result in misreadings and injuries.
These are general tips. Always review the specific instructions that come with your multimeter to ensure you’re using it safely and correctly.
Understanding Your Multimeter
First, locate your multimeter’s on/off switch. Then, familiarize yourself with its display, whether you’re using a digital or analog multimeter. If it’s an analog multimeter, it’ll have a meter pointer in the form of a straight line that’ll point to numbers on different metric scales. A digital multimeter will simply display a number.
Find the selector knob, which you can use to select the metric you want to measure. Alternatively, there might be a set of buttons that you can use to make your metric selection.
Next, identify the location of the multimeter’s jacks or ports. Most meters have three or four ports, and each port serves a specific function. All multimeters will have a black common port labeled COM. This is a grounding or neutral port. The red port with the 300mA label can measure up to 300 milliamps. The red port with the V Omega (V Ω) label works with most millimeter measurements and will measure in milliamps. The red port with the 10A label can handle up to 10 amps.
Usually, multimeters also come with probes or leads that plug into their ports. Black probes always plug into COM ports, while red probes, also called positive or hot wires, plug into whatever port can support the desired measurement. The probes also come with alligator clips to keep operation hands-free.
Safety Tips for Multimeter Operation
It’s imperative that you take all necessary precautions when using a multimeter. Not doing so can lead to injury or even death due to electrocution. Turn off power to the circuit you’re testing and unplug any devices from the socket.
Start your safety check by ensuring that you’re using updated technology. An older model may be more prone to malfunctioning, which can lead to dangerous accidents. After confirming that you’re using a current device, inspect it for any physical damage. If necessary, replace it or have it repaired, and make sure it tests successfully on a proving unit before using.
As a general rule, always assume the multimeter is reading an electrical current unless you’ve completely turned it off. Use protective gear and equipment every time you use a multimeter. Protective gloves, rubber mats, protective headwear and clothing that completely covers your skin will maximize your safety while you’re operating multimeters. When using the probes, don’t touch the probe tips and don’t let them touch each other.
When using a multimeter, never work alone. Have another person around to spot any safety risks that arise. Be completely aware of your surroundings. While multimeters are extremely useful tools, they’re also sensitive devices that you need to handle vigilantly. Keep checking your multimeter’s display while you work, since it might flash a warning if it detects faulty device operation.
Avoid using a multimeter in moist and humid environments. Water content can conduct electricity, which puts you at risk for electrocution if you’re around it while using a multimeter.
How to Test
First, turn the dial to the measurement you want to test: AC voltage, DC voltage or resistance. Then, insert the black probe into the COM port and the red probe into the V Ω port. Next, connect the test probes to the electrical circuit: black probe first, red probe second. After viewing the reading on the display, remove the probes from the electrical circuit: red first, black second.
Measuring With a Multimeter
If you’re dedicated to your machinery, a multimeter is a fantastic tool to have in your arsenal. However, it’s not safe or effective to use without proper technique. Revisit this article whenever you need a refresher on how to use your multimeter without injury or error.