In this article, we will talk about how to make the correct use of the multimeter to measure electrical current, as it is very common to have doubts when it comes to measuring electrical current with a multimeter. Seeing this, we decided to talk a little more about this subject, for example, showing what is the difference between ammeter, clamp meter and a multimeter, in addition to explaining what electrical current is, magnitudes and amps.
Do you know what electrical current is?
Before we learn what electrical current is , we need to understand what an electrical quantity is. Greatness is basically everything that can be measured or quantified, such as voltage, power, resistance and electric current, which are the main magnitudes of electricity, where its units of measurement are respectively represented below:
- Voltage = Volts (V)
- Power = Watt (W)
- Resistance = Ohm (Ω)
- Current = Ampere (A)
Electric current is one of the main magnitudes of electricity and is defined by the ordered movement of electrons, and its unit of measurement is given in amperes (A). The electric current can be continuous or alternating, that is, it can vary its value and direction as a function of time.
What is the difference between ammeter, clamp meter and multimeter?
There are several devices that make it possible to measure the electric current, such as the ammeter, clamp meter and the multimeter. The ammeter is a specific device for measuring electric current and must be connected in series with a circuit so that the resistance must be zero to obtain the measurement, as the electric current passes through the ammeter.
With the clamp meter it is not necessary to place the device in series with the circuit, as the clamp meter measures through induced electric current that passes through the pliers, due to its interaction with the electromagnetic field generated around the conductor.
The clamp meter has a claw to measure the electric current, which must be placed on only one energized conductor. Because by placing the clamp clamp on two or more conductors, the electromagnetic field of one conductor cancels the other, that is, there will be no induced electric current passing through the clamp meter.
With the multimeter it is possible to carry out various measurements, such as, for example, measure electrical current, voltage, resistance, diode, capacitance, frequencies and other electrical quantities more accurately.
Thus, we can highlight that the difference between multimeter, ammeter and clamp meter is that the ammeter is capable of measuring only the electric current, while the multimeter is capable of making other measurements. In addition to making other measurements, the clamp meter is the most recommended to measure electrical current of greater intensity, as there is no direct contact with the electrical conductor.
How to use the multimeter to measure electric current?
After all the explanations about ammeter, clamp meter and multimeter, now we will explain how to use the multimeter to measure electric current. There are basically two types of multimeter, the digital multimeter and the analog multimeter, but currently the most used is the digital multimeter, due to its ease of reading and use, but the two multimeters are based on the same principle.
However, multimeters are not recommended to measure electrical current of greater intensity, as they have a low capacity to measure electrical current, and if this current is exceeded it can damage the multimeter and put the user at risk. Therefore, clamp meters should be used.
How to use multimeter: Step by step.
For your safety, we must turn off the circuit power, turning off the respective circuit breaker or the general circuit breaker before using the multimeter to measure electrical current, whether in residential, building or industrial installations.
Now with the multimeter in hand you must rotate the rotary selector until you reach the electric current scale, which is represented by the symbol (A), but pay attention to the scale, as it must correspond to the circuit to be measured, that is, if is direct current or alternating current.
Note that on some multimeter models, there are three or more types of terminals on the multimeter. Usually one terminal is black (COM), which must be connected to the black probe and the other two terminals are usually red. One will have an (A) ampere and will also be reporting the maximum electrical current supported by the multimeter, for example, 10A or 20A. And it is to this terminal that the red test lead must be connected, that is, it must never connect to another terminal, because it is used to measure other electrical quantities.
The multimeter’s probes should be connected in series with the circuit turned off, for this, make a cut in the conductor, to obtain two probes, which we can call them A and B. Place the red probe in the conductor’s A tip and the black probe on tip B of the conductor and isolate. Now you can energize the circuit, thus obtaining the values of the electric current that passes through this conductor, but always remember to amend the cut and isolate it.
In this video of the World of Electrical you can see in much more details how to measure electrical current with a multimeter, just check it out!