NEIEP Mechanics Practice Exam

How should ammeters be connected in order to measure current in a circuit?

1. In parallel with the load

2. In series with the circuit

3. In parallel with the power source

4. In series with the power source

The correct answer is: In series with the circuit

To measure current in a circuit accurately, ammeters must be connected in series with the circuit. This configuration ensures that all the current flowing through the circuit also flows through the ammeter. Since an ammeter is designed to measure the flow of electric charge, placing it in series allows it to read the actual current without inadvertently altering the circuit's behavior. When in series, the ammeter does not create any significant resistance in the circuit, which could affect the current and create inaccurate measurements. This direct path allows the ammeter to display the correct value of the current flowing at that point in the circuit. Other connection methods, such as connecting an ammeter in parallel with the load or power source, would prevent it from measuring the current accurately. These configurations can lead to short circuits or excessive current flowing through the ammeter, potentially damaging it and giving incorrect readings.