We don’t need to be schooled on how electricity concerns our daily activities, and for safer handling of the electrical systems we deal with, it is important we have a good understanding of it.
Electricity is complex due to its various aspects, there are also different devices that could be used to measure the different categories of electricity, and one of them is the clamp meter.
The clamp meter is used by electricians and DIY enthusiasts to measure direct currents, Alternating currents, DC voltage, AC voltage, resistance, and other aspects of electricity, like frequency, continuity, temperature, capacitance, and a lot more.
For this article, we will focus on how you can use the clamp meter to measure direct current with the clamp meter.
Understanding DC amps and the clamp meter
Before we go into in-depth explanations on how you can measure DC amps with a clamp meter, we would begin by giving a summary of the DC amp and the clamp meter so you have an understanding of how they relate.
Talking about electricity by mentioning current would be easier; the current is the flow of electricity through a circuit or a conductor, and it is measured in an ampere. The flow of current could be direct or alternated; direct current is denoted as “DC,” and it differs from alternating current in that it flows in a constant direction.
Vehicles and most home appliances powered by batteries run on direct current; other DC sources are solar cells and thermocouples. So when your car or battery-powered device stops functioning properly, the necessary thing would be to perform a test on it, which you can carry out with a clamp meter.
A clamp meter is a current measuring device that can also function as a multimeter. It can be used to troubleshoot electricity, but unlike the multimeter and other current measuring devices, it is more convenient and even safer to use because you don’t have to break the circuit before you get a reading.
How the clamp meter work
When the current flows through the conductor, the clamp meter takes contactless readings using a semiconductor Hall Effect to measure the axial magnetic field generated in it.
When the clamp surrounds the wire, it creates a magnetic field according to Ampere’s Law; the magnetic field is concentrated by the iron core contained in the clamp.
While the current flows through the wire, the clamp meter senses the magnetic field within the air gap that contains the Hall Effect detector and forces a deflection on it. The deflected silicon chip then creates a voltage perpendicular to the path of the electron flow.
The clamp meter uses an internal microprocessor to convert the voltage to amps and gives the current reading. The working of the clamp meter may seem complicated, but it limits what you have to do, mostly putting the clamp ring around the wire to take a reading.
How to measure DC amps
To measure the current flowing through your circuit, it is more than just selecting DC Amps, opening the jaws of your clamp meter, closing it around a wire, and viewing the reading; it is also necessary to endure your safety while performing the DC amps measurement.
You have to ensure you are safe while you measure DC amps; the first thing to do is to make sure the test probes are disconnected from the clamp meter. Another safety tip is to keep your fingers behind the tactile barrier on the face of the clamp meter while taking the direct current measurement.
Now that we have established some safety tips, turn the dial on the clamp meter to A dc. Your device would display a jaw-shaped clamp holding a dot in the middle, which shows that the measurement you are about to take is from the jaw of your meter.
To ensure your DC amps measurement is accurate, make sure the jaws of your meter are closed and there is no conductor inside or close to it. Wait for the display on the clamp meter to be stable, then press the zero button. The zero buttons on your meter is designed to remove DC offsets. It works only when the dial is set to measure direct currents.
Now press the clamp release to open the jaws, close it around the conductor you want to measure, then use the alignment marks on it to center the wire, and your clamp meter will display a reading.
Also note that when you measure DC amps, the dot held by the jaw-shaped clamp on your meter will flash on and off to indicate that the current your clamp meter reads is less than half amps, but the dot would stay steady when it the current measured more than half an amps.
Conclusion
A little bit more understanding of the clamp meter is required before taking any measurement with it, so we have explained the clamp meter and how it works; we have also described how you can use the device to measure DC amps.
You also have to know the direction of the current while testing, so when the clamp meter senses the magnetic field from the flowing current, it indicates a plus or minus reading. Also, the clamp ring suggests polarity with an arrow.
To carry out this test, get yourself a clamp meter that can read DC amps; most clamp meters are built to measure only alternating currents, and just a few measure direct currents.
The direct current clamp meters are useful not only for DIY enthusiasts but also for power supply and battery industries.
Your explanation is straight from an instruction manual of a particular clamp meter brand & model. It would have been useful to quote the model since different meters have different features.