Electric circuits – WJECMeasuring current and voltage
Engineers connect components in electrical circuits in series or parallel to make a range of useful circuits. We can calculate the voltage, current and resistance in these circuits.
You need to know how to measure the current that flows through a component in a circuit and the voltage across it.
Figure caption,
The ammeter is in series with the lamp
Measuring current
Current is measured in amperes. Amperes is often abbreviated to amps or A. The current flowing through a component in a circuit is measured using an ammeter. The ammeter can be placed anywhere in the circuit. Remember that the current is the same in all parts of a series circuit.
Voltage
A voltage (or potential differenceThe potential difference (or voltage) of a supply is a measure of the energy given to the charge carriers in a circuit. Units = volts (V). This is the voltage between two points that makes an electric current flow between them.) across an electrical component, such as a lamp, is needed to make a current flow through it. Cells or batteries often provide the voltage needed.
Measuring voltage
Voltage is measured in volts, often abbreviated to V.
Figure caption,
The voltmeter is in parallel with the lamp
The voltage across a component in a circuit is measured using a voltmeter.
The voltmeter must be connected in parallel with the component.