Ammeter is connected in series

The idea

An ammeter measures electric current and is always connected in series in the circuit through which the current is to be measured.

Measuring the current

A student wants to measure the electric current that flows through a torch bulb. An instrument called an ammeter is used for this.

How should the ammeter be joined in the circuit?

• In the path of the current, one after the other with the bulb
• Across the two ends of the bulb, as a second path
• Away from the circuit, near the cell only

Where the ammeter goes

Press Next step to open the circuit and put an ammeter in the gap.

In line with the bulb

The ammeter was placed in the gap, so the current flowing through the bulb had to pass through the ammeter as well. That is what in series means here: joined end to end in one path.

An ammeter measures electric current and is always connected in series in the circuit through which the current is to be measured.

Notes

An ammeter measures electric current and is always connected in series in the circuit.

Check yourself

How is an ammeter connected to measure the current in a circuit?

What does an ammeter measure?

To measure the current in a bulb, which change to the circuit is correct?

• In parallel, as a second path across the bulb. An ammeter is always connected in series. A parallel connection is not used for it.
• In series, in the path of the current — correct. Yes!
• Outside the circuit, away from the wires. The ammeter has to be in the circuit through which the current is to be measured, in the path of that current.
• The charge stored in the cell. Stored charge is not what an ammeter shows. It measures the current in the circuit.
• The brightness of the bulb. An ammeter does not measure brightness. It measures electric current.
• The electric current in a circuit — correct. Yes!
• Open the wire at one place and join the ammeter into that gap — correct. Yes!
• Leave the circuit as it is and join the ammeter from one end of the bulb to the other end. That joins the ammeter across the bulb, in parallel, and an ammeter must be in series.
• Replace the bulb by the ammeter and remove the cell. The ammeter has to sit in the circuit through which the current is to be measured, along with the cell and the bulb.