You measure current in a series circuit (or any circuit) using an ammeter.

Here's why:

* Ammeters measure current: They are designed to be placed in the path of the current flow to measure the rate of charge passing through a point.

* Series circuits have the same current throughout: In a series circuit, all components share the same single path for current, so the current is the same everywhere in the circuit.

Let me know if you'd like to know more about how to connect an ammeter in a circuit!