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Alternating Current vs Direct Current

The way which electricity can flow can be either through a direct current (DC) or in an alternating current (AC). The main difference between the two is the direction within the conductor, like a wire, the electricity will flow. There are both advantages and limitations that come with each power transmission, and particular needs for specific power supplies. The Local Electrician has been working with electrical systems for over 25 years, meaning we understand there uses. Our Level 2 Electrician operators work with both direct and alternating currents and know the main differences and similarities between them.

The direction which the alternating current (AC) and direct current (DC) transfer electricity is their main difference. Alternating currents continue to switch the direction of the electrons, for instance travelling forward then going the opposite way. Whereas, direct currents keep the electrons on one path in a steady way by always going forward. 

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The Origins of AC and DC Flow

DC Power Origins

Thomas Edison was the primary creator of the first DC battery. By a magnetic field is close to the wire, it makes the electrons travel in one direction on the wire. This is because they repel from the negative side but then are attracted to the positive side, travelling in that direction. As a result, Edison used this information to establish the DC current flowing through a battery.

AC Power Origins

The DC battery was replaced more often due to the ac voltage generators created by Nikola Tesla. Tesla discovered that instead of using the magnetism along the wire, she used a rotating magnet. After orientating it in one direction, the electrons travelled to the positive, then when the orientation was flipped, they travelled back. As a result, these systems are used more in cities as they transmit extra power over long distances more efficiently.

Characteristics and Comparisons of Each Power Distribution Systems


  • Amount of Energy which can be Transferred – longer periods and over longer distances
  • How the Direction of Flow is Made – A magnet is rotated with the wire
  • Frequency of the Electric Charge – depending on the country, it can be around 50Hz to 60Hz
  • The direction which the Current Travels – periodically reverses in its direction while moving within the circuit
  • Current – the current is of magnitude level and varies with time
  • The Flow of the Electrons – directions change from forwards to backwards constantly
  • Power Provider – through a power plant, AC generator and/or mains
  • Passive Paramterers – between 0.1 and 1
  • Different Types – square, trapezoidal, sinusoidal and also triangular


  • Amount of Energy which can be Transferred – loses energy the further the energy travels which means it is limited
  • How the Direction of Flow is Made – regular magnetism occurs along the wire
  • Frequency of the Electric Charge – the frequency of this current met at zero
  • The direction which the Current Travels – once simple direction when flowing within the circuit
  • Current – constant magnitude is the current
  • The Flow of the Electrons – the main direction of the electrons is forward or one way
  • Power Provider – either a battery or through a cell
  • Passive Paramterers – always set at 1
  • Different Types – mostly likely pulsating or pure

Uses of the Different Currents

The amount of energy the different currents can carry determines how each one is generally used.

For DC currents, the voltage source is often within a battery or cell as the current cannot travel far. The battery is made for the purpose of giving one voltage, with the further it travels the less amount of energy is contained.

For AC currents, they are more popularly used for providing electrical energy around a suburb, city and so on. From a generator in a power plant to a device called a transformer, electrical energy is provided. These transformers can increase or decrease the amount of electricity given to a location. Additionally, they are located on the street, transmitting power/ voltage suitably to what the electrical appliance needs. For more information on transformer boxes, we have additional information on their positive benefits.

Positives and Negatives of AC Currents


  • AC currents are lower in cost because they are available in large amounts. Providing more power with lower costs than DC, they are more efficient and beneficial to use
  • Power transmission is more efficient because of the steady transmission of power through the resistance allowed longer-lines to travel further. As a result, it is now easier to transmit power across long distances in a more regular and contained manner
  • Power consumption is possible through utilising AC currents, where appliances like electric fans and compressors in air conditioning us this system
  • Power generation is possible because of the invention of the AC generator. The hydroelectric AC generator was later invented, still used in today’s times, providing more generation of power to occur


  • AC currents being used in cars is more expensive when charging
  • Insulation is needed because of high voltages present, insulation can help control safety but it can be more dangerous to work with AC
  • Heat and sparks happening is an issue with AC currents which can lead to electrical shocks and fires

Positives and Negatives of DC Currents


  • DC currents allow electricity to flow in one direction, making it easier to handle
  • More suitable for semiconductors, transistors and also LEDs


  • The voltage power is less meaning less power overall can be generated
  • Cannot travel across long distances, as more power is lost the further the electricity needs to go

Expert Level 2 Electrician Sydney

The Local Electrician and our experienced Level 2 Electrician workers understand all there is with both AC and DC currents. We are able to be called out to work on any type of electrical job in relation to the different currents. Moreover, we are accessible to all Sydney suburbs, and through our Emergency Electrician Services, are open 24/7 for hiring.

Importantly, we work with extreme safety and efficiency with both AC and DC currents because they can be extremely dangerous if incorrectly handled. We follow the Safe Work Australia guidelines at all times when working with voltage and other risks with electricity. No matter the job when dealing with AC or DC currents – call us on 0439 823 1… or email us at info@thelocalelectrician.com.au.


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Our skilled electricians are qualified to carry out any electrical repair or installation within Sydney. We strive to deliver absolute customer satisfaction by offering electrical services that are affordable, safe and long lasting.

Hamish Baker