Electric current and voltagePrint
You need to know how to measure current and voltage.
Current is a measure of how much electric charge flows through a circuit. The more charge that flows, the bigger the current.
Current is measured in units called amps. The symbol for amps is A. For example, 20A is a bigger current than 5A.
A device called an ammeter is used to measure current. Some types of ammeter have a pointer on a dial, but most have a digital readout. To measure the current flowing through a component in a circuit, you must connect the ammeter in series with it.
Voltage is a measure of the difference in electrical energy between two parts of a circuit. The bigger the difference in energy, the bigger the voltage.
Voltage is measured in volts. The symbol for volts is V. For example, 230V is a bigger voltage than 12V.
Voltage is meaured using a voltmeter. Some types of voltmeter have a pointer on a dial, but most have a digital readout. To measure the voltage across a component in a circuit, you must connect the voltmeter in parallel with it.
You can measure the voltage across a cell or battery. The more cells, the bigger the voltage.
|Measured in||amps, A||volts, V|
|Measured with||ammeter in series||voltmeter in parallel|
|Circuit symbol of measuring devise|
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