When measuring current, the ammeter is placed in:

• A. In parallel across the load
• B. Across ground
• C. In series in the circuit
• D. Across the power source

Answer: (C)

To measure current, the ammeter must be placed in series with the circuit path that carries the current. When the meter sits in series, the same amount of current that flows through the load also flows through the meter, so the device can accurately count the electrons passing through. Ammeters are designed with very low internal resistance to minimize any voltage drop and avoid disturbing the circuit.

Placing the meter in parallel with the load would create an alternate path with little or no resistance, drawing current away from the load or potentially creating a short circuit, which would distort the measurement and could damage components. Placing it across ground or across the power source would not measure the load current at all; it would instead measure something else and again fail to reflect the actual current through the circuit.

So, the correct setup is to insert the ammeter in series in the circuit.