How to Read Voltage Meter Readings: Tips and Tricks for Accurate Results
Are you operating in the worlds of electrical engineering, energy, R&D, telecommunications or manufacturing? If so, or we haven’t mentioned your industry, you may already have a voltage meter in the toolbox, because it’s the easiest, safest and most accessible way to master the critical and yet eminently dangerous phenomenon of voltage – the electrical potential difference between two points of an electrical circuit.
Believe it or not, voltage meters – also known as voltmeters but these days regularly packaged as a feature of multimeters – date all the way back to the late 19th century, when Edward Weston ingeniously discovered that he could measure the voltage drop across a known resistance. Rather than needing a physical coil mechanism and needle, however, today’s voltage meters employ clever digital electronics that simply, safely and accurately give an instant voltage reading.
Struggling to use your voltage meter, or looking to upgrade to something more sophisticated, safe and accurate? There’s a surprisingly vast range of affordable voltage meter types in the modern range, but the basic steps for using them are all fairly common:
1. Power down the circuit
Before doing anything, eliminate the risk of electric shock or equipment damage by completely powering down the circuit. This involves uplugging devices and turning off the power source.
2. Set up the meter
Some voltage meters will require you to set a specific voltage measurement range, with the setting you choose dependant on the range you want to detect or measure. You’ll need to consult with an expert or the manual for the precise steps, but it’s normally just a matter of flicking a dial or switch and checking the display.
3. Test the meter
It’s not necessarily critical to test the voltage meter for accuracy each and every time you use it, but it should be done regularly. The process of calibration differs with each meter model, but the principle is always the same – to connect the device to a circuit with a known and independently verified voltage level, and check you’re getting the same reading on your device.
4. Connect the meter
Most typical voltage meters feature probes, which the user simply connects to the circuit to be measured. Remember, the red (positive) probe connects to the point of the circuit with the higher voltage potential, with the black (negative) probe on the lower voltage end. You’ll need to:
* Determine the circuit’s voltage source
* Determine the polarity (red connects to the positive terminal, black connects to the negative terminal).
5. Turn on the power
Your voltage meter won’t give you a reading at all with the power off, so plug the devices back in and power them up at the power source, breaker or switch.
6. Take your reading
With the power on, the digital display will simply show you the accurate voltage reading, which may be in volts (V) or millivolts (mV). If the detected voltage is higher than the voltage range you set in step 2, you may simply see an error code.
7. Power down, disconnect, restore the power
Keep those hands away from live circuits, so turn off your voltage meter and power down that circuit once again. Now disconnect the probes from the circuit before restoring the power and getting back to work.
Remember, voltage meters are best used by authorised, skilled and experienced personnel who are fully up-to-date with contemporary electrical safety procedures, but there are no specific laws or regulations in Australia prohibiting an untrained person from taking a simple voltage reading. For the most accurate and safe use, however, these tips can really help:
6 final tips for safely using your voltage meter
* Read the manual carefully, as your particular meter has various features, functions and functionality
* Check the batteries, which should be properly installed and fresh
* Don’t rush when using a voltage meter, as working with electricity is dangerous and expensive electrical equipment is easy to damage
* Ensure correct polarity when connecting the probes, as the result can be poor readings and even damage to certain sensitive components such as diodes and electrolytic capacitors
* Be patient when taking those readings, as the meter may need time to stabilise before presenting an accurate final reading
* Store your meter properly, protecting it especially from damage, dust and moisture.
Voltage meters are an essential tool for any organisation working with electrical circuits, but the one you need depends on your specific requirements, workplace conditions and the desired features and price-point. If you need a little guidance, our specialist guides would be delighted to assist. RS has a full range of voltage meters to suit any job.