Final answer:
An ammeter is used to measure the rate of electric current in a circuit and must be connected in series with the circuit component. It has a very low resistance to avoid affecting the circuit and commonly includes a fuse for protection against high currents. Ammeters can have different ranges, such as 20.0-A or 100-mA full-scale, for various application needs.
Step-by-step explanation:
The purpose of the ammeter, or milliammeter, is to measure the rate of electric current flowing through a circuit. When measuring the current, the ammeter must be connected in series with the component in the circuit to ensure that it measures the entire current flowing through that branch. The ammeter is designed to have very low resistance, often a fraction of a milliohm, to minimize its impact on the circuit's performance and provide an accurate reading of the current without significantly altering it.
To prevent damage from high current, ammeters are usually equipped with a fuse. It is critical to have this protective device because if the current exceeds the ammeter's capacity, it could lead to malfunction or permanent damage to the instrument. This is why ammeters are often constructed to accommodate different ranges of current, such as a 20.0-A full-scale or a 100-mA full-scale reading, thereby allowing them to be used in various applications, from heavy industrial settings to delicate electronic devices. Understanding the internal construction and correct connection of the ammeter can shed light on the applications of series and parallel connections in electrical circuits. This knowledge is also vital in various practical scenarios, including automotive diagnostics, consumer electronics such as cell phones and digital cameras, and even in professional audio equipment such as tuner amplifiers, where precise current measurements are essential.