Measuring Electricity – Voltage and Current – Lesson Summary

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Learning Objective

In this lesson we will learn how electricity can be measured in terms of voltage and current.

Learning Outcomes

By the end of this lesson you will be able to:

  • Define voltage and explain how it can be measured using a voltmeter.

  • Define current and explain how it can be measured using an ammeter.

  • Compare the distribution of voltage and current in series and parallel circuits.

  • Explain the use of transformers in electrical devices.

 
measuring electricity current and voltage

(Image: kritsadaj, Pixabay)

Lesson Topics

1 | Measuring Electricity

2 | Voltage

3 | Current

4 | Electricity Supply in Australia

5 | Transformers

6 | Voltage and Current in Series and Parallel Circuits

7 | Comparing Parallel and Series Circuits with Multiple Light Bulbs

8 | Summary

Lesson Summary

  • Voltage is a measure of the electric potential energy in an electric circuit.
  • It is measured in volts (V), using a voltmeter connected in parallel.
  • Supply voltage is the energy supplied by a power source.
  • Voltage drop is the energy used by a component.
  • Current is a measure of the electric kinetic energy in an electric circuit.
  • It is measured in amperes (‘amps’) (A), using an ammeter connected in series.
  • The domestic electricity supply in Australia is 230 V, with a maximum current of 10 A from a standard power point.
  • Transformers reduce supply voltage for devices requiring lower voltage.
  • When components are connected in series:
  • Voltage is shared.
  • Current is not shared.
  • When components are connected in parallel:
  • Voltage is not shared.
  • Current is shared.
  • Light bulbs connected in parallel will be brighter than light bulbs connected in series, if the supply voltage and light bulbs are the same.
  • Adding another light bulb in parallel will not affect the brightness of other bulbs, but adding another light bulb in series will reduce the brightness of all bulbs.
  • Light bulbs connected in parallel can be controlled by separate switches and are not affected by other bulbs blowing.
  • Light bulbs connected in series can only be controlled by a single switch and are affected by other bulbs blowing.

 
ammeter

(Image: SV1XV, Wikimedia Commons)

(Header image: foray, Adobe Stock)