Review the key terms and skills related to voltmeters and ammeters, including where to place them in a circuit.
|Instrument used to measure current.
|Instrument used to measure electric potential difference.
How are ammeters and voltmeters represented in a circuit?
Ammeters are typically represented by a circle with a letter A inside (Figure 1). Voltmeters are typically represented by a circle with a letter V inside (Figure 2).
How to use ammeters and voltmeters
Ammeters measure the current through components. To measure the current going through a component, the ammeter is connected in series with the components we want to investigate. Resistors in series experience the same current (Figure 3). Typically, ammeters have negligible resistance, so they do not affect the circuit.
For example, if we want to find the current through
in the circuit below, the ammeter is placed in series with .
Voltmeters measure the electric potential drop across components. The voltmeter is placed in parallel with the component of interest because components in parallel experience the same potential difference.
For example, if we want to measure the electric potential drop across resistor
, the voltmeter should be arranged in parallel with the resistor ( ).