Electric current is measured using a device called an ammeter or an amperemeter. The unit of electric current is the ampere (A). There are a few different methods to measure electric current, but the most common one involves placing the ammeter in series with the circuit in which the current is flowing.
Here's a step-by-step explanation of how electric current is measured:
Select the appropriate ammeter: Choose an ammeter with a suitable current rating that can handle the expected amount of current in the circuit. Using an ammeter with a lower current rating than the actual current can damage the ammeter and create safety hazards.
Open the circuit: To measure the current, you need to insert the ammeter into the circuit. This usually involves opening the circuit at a specific point to insert the ammeter in series. In other words, the ammeter becomes part of the current path.
Connect the ammeter: Connect the ammeter in series with the circuit. This means connecting the positive terminal of the ammeter to the positive end of the circuit and the negative terminal of the ammeter to the negative end of the circuit. In series connection, the same current flows through both the circuit and the ammeter.
Close the circuit: Once the ammeter is connected in series, close the circuit by rejoining the open ends.
Read the current: The ammeter will display the value of the electric current in the circuit. Make sure to read the measurement accurately, and if the ammeter has a range selector, ensure that it is set to an appropriate scale to get an accurate reading.
Interpret the reading: The electric current reading is usually given in amperes (A). If the ammeter has multiple scales, you might need to consider the scale factor while interpreting the measurement.
It's important to note that in some cases, non-contact methods like using clamp meters can be employed to measure current without physically opening the circuit. These meters work based on the principle of magnetic induction and can be useful when dealing with high currents or situations where it's not practical to interrupt the circuit.
Always exercise caution while measuring electric current, and if you are unsure about the procedure or safety precautions, it's best to seek assistance from a qualified electrician or a knowledgeable individual.