In the recent chapter we learnt about electricity, types and where it really comes from. In this chapter we shall learn about types of current electricity, their difference and applications.
As explained earlier current electricity is the flow of electrons in a circuit. There are only two types of current electricity classified according to the difference in their polarity and direction of current flow.
Types of electric current
Electric current is also known as current electricity. It is of two types namely;
Direct current and Alternating current.
Direct current.
It's the most common type of electric current, it has a linear direction of motion as shown in the animation below.
Current moves from the positive polarity to negative pole but electrons moves in the opposite direction. As seen above you can notice easily that it has a constant polarity.
It can be generated from many sources like batteries, solar panels, thermocouples, DC dynamo etc.
It is mostly used in portable electronics due to their ease of generation. 90% of the portable electronics market share is powered by DC even, mordern electric cars now run on DC supplied from batteries.
Applications of DC.
DC is used in many devices examples are listed below.
Street lights
Automated doors
Electric cars
Power banks
Surgically-implemented electronics
Rechargeable devices
Emergency electronics.
Alternating current.
This type of electric current has an alternating polarity as shown below, its polarity as shown below its polarity changes with time depending on it sources.

When an AC changes polarity from one to another once, it is called a cycle. When it completes a number of cycles per unit time it is called frequency (Hz), 99% of AC used in the world is generated from an alternator which consists of copper coils wound on a laminated soft iron amarture and made to rotate in a magnetic field by applying an external force.
AC can only be generated from motors but through advancing technology DC can be converted to AC by means of oscilators.
Applications of AC.
Due to their properties and ease to generate it is use for the following;
It is use to power high current consuming machines
It is use for powering industrial robotic arms
It is mostly used to for generating radio waves and wireless power transfer.
It is use for transmitting sound waves and video signals over long distance.
Difference between AC and DC.
AC differs from DC mainly because of the polarity. The difference between AC and DC are listed below.
AC has an alternate polarity due to the periodic change of movement of electrons from negative to positive pole while DC has a constant polarity.
AC can be converted to DC by rectification with diodes, DC can be converted to AC with oscillators which switches it on and off repeatedly at high speed.
AC is required in high power or wattage electronics while DC is use to power low wattage devices.
AC is generated from dynamos at high voltage and then transmitted over long distance wires which is furtherly step down at consumer units. DC in contrary to this can't be transmitted at long distance due to voltage loss.
AC is cost to produce and keep running, because it can only be produced from dynamos and inverters,while DC is relatively cheap to produce from sources like batteries, thermocouple, bio gas etc.
Many of our portable electronics works on batteries which are charged by an AC-DC converter circuit fed with AC. In some developing countries home appliances still depends fully on AC to operate.
Both AC and DC has their various applications, so they are both important in electronics.
Tags:
Basic Electronics