Ammeters are instruments used to measure electric current in a circuit. They work based on the principle of amperage, which is the flow of electric charge through a conductor. The primary function of an ammeter is to measure the amount of current passing through a specific point in a circuit.
To measure current, an ammeter needs to be connected in series with the circuit. This means that the current flowing through the ammeter will be the same as the current flowing through the rest of the circuit elements. When you connect an ammeter in series, it becomes part of the conductive path, and the current will flow through it, allowing the ammeter to measure the magnitude of the current.
Here's a step-by-step guide on how ammeters measure current in a circuit:
Circuit interruption: To install an ammeter in a circuit, the circuit needs to be temporarily interrupted. This is usually done by breaking the circuit and connecting the ammeter in line with the path of current flow.
Series connection: The ammeter is connected in series with the circuit, which means that it is inserted in-line with the components carrying the current. When connected in series, the ammeter has the same current passing through it as the rest of the circuit.
Low resistance: Ammeters are designed with very low resistance, ideally close to zero, so that they do not significantly affect the current in the circuit. This ensures that the ammeter doesn't create a significant voltage drop or disturb the normal operation of the circuit.
Current measurement: As current flows through the circuit and the ammeter, it creates a potential difference (voltage) across the ammeter's low-resistance internal coil. The ammeter is calibrated to measure this voltage, which is directly proportional to the current passing through it.
Reading the current: The ammeter is equipped with a scale or a digital display calibrated in amperes (A) that shows the value of the current being measured. You can read the current value directly from the scale or display.
Circuit restoration: After taking the current measurement, the ammeter is removed from the circuit, and the circuit is restored to its original state.
It's important to note that ammeters have their own limits in terms of the maximum current they can handle. Exceeding this limit can damage the ammeter or pose a safety hazard, so it's essential to select an appropriate ammeter for the current range you want to measure.