In the world of electricity, two main types of current predominate: alternating current (AC) and direct current (DC). These currents, with their different characteristics and applications, play a vital role in powering our modern world. But what makes them different? How do they behave and where do they find their application? What is the difference between alternating and direct current?
This comprehensive article aims to shed light on the key differences between AC and DC. We will look at their behaviour, generation methods, transmission options and applications in various industries. Whether you're an electronics hobbyist, a student, or just curious about the inner workings of electricity, this guide will provide you with a solid understanding of alternating and direct currents.
What is alternating current?
Alternating current, also known as AC current, changes its polarity and magnitude periodically and continuously with respect to time. Alternating current can be obtained by using an alternator that produces alternating current.
Applications of AC
- Alternating current is used for long distance transmission in offices and homes;
- The power loss of AC is less, so it is widely used in transmission;
- Alternating current can be converted from high voltage to low and from low to high efficiently by using a transformer;
- AC is used in larger applications and appliances such as freezers, air conditioners, dishwashers, washing machines, fans and light bulbs;
What is direct current?
Direct current, also known as direct current (DC), is a unidirectional flow of current or electrical charge that, unlike alternating current, does not change magnitude or polarity with time. Direct current has a constant magnitude and direction, and since the direction and magnitude do not change, the frequency of direct current is zero. The electrons in the direct current move from high electron density to low electron density.
We can obtain a direct current from an alternating current using a process called rectification, and the device that does this is called a rectifier.
Applications of direct current
- Direct current is widely used in small electronic devices and gadgets.
- Direct current is not suitable for long distance transmission, but storage of direct current is easy in the form of battery.
- Direct current is used in mobile phones, portable computers, radios and other electronic gadgets.
- Direct current is used in flashlights
- Direct current is used in electric and hybrid cars and in automobiles
Difference between AC and DC
- Alternating current changes direction as it flows, while direct current does not change direction as it flows and remains constant.
- The alternating current has a frequency that indicates how many times the direction of the current changes during flow, while the frequency of the direct current is zero since it does not change direction.
- The power factor of alternating current is 0 to 1, while that of direct current is a constant zero.
- The alternating current is generated by the alternator while the PV cells, generators and batteries generate the direct current.
- The AC load can be capacitive, inductive or resistive, but the DC load is always resistive.
- The DC current graph has a constant line indicating that the magnitude and direction are constant, while the AC current can be a sine wave, square wave, or triangular wave.
- Alternating current is converted to direct current using a device called a rectifier, while direct current is converted to alternating current using an inverter.
- Alternating current is widely used in industrial equipment and consumer electronics such as air conditioners, freezers, coolers, washing machines, lights and fans; while direct current is used in electronic gadgets and small devices such as watches, laptops, mobile phones and sensors.
- Alternating current can be transmitted over long distances with some loss, while direct current can be transmitted over very long distances with very little loss using HVDC.