Direct current (DC)
The Direct current (DC) is simply electric current that flows in one direction. It usually flows from a battery source. It also means electric current with one polarity of current or voltage.
Uses of DC
DC is often used to power low voltage appliances such as flashlights, toothbrushes, calculators, telephones and so on, although it can also power high voltage appliances.
Sources of Direct Current Supply
Common sources of DC supply includes solar cells, batteries and DC generator.
Drawback of Direct current (DC)
The major drawback of Direct current (DC) is that it cannot be transmitted through long distances without considerable power loss. The power plant or source of direct current (DC) supply must be within 3km of the appliance which implies that direct current power plant/supply must be installed in every household.
Alternating Current (AC)
Alternating current rapidly changes in direction. AC is transferred at very high voltage (kilovolts) over long distances and then stepped down with a transformer to between 100-240 volts at point of use.
Uses of AC
AC is often used to power appliances that require higher voltages examples include fans, air conditioners, cookers, tvs , water heaters, pressing irons and so on
Advantage of Alternating Current
The major advantage of AC is that it can travel hundred to thousands of kilometers without considerable power loss making it possible for the location of central alternating power supply stations far from point of use.
Comparing Alternating to Direct Current
It can be argued that AC holds no practical advantage over DC. As stated earlier, DC is preferred over AC for low voltage appliances while AC is preferred to DC for high voltage appliances. However it is possible to build power supply/distribution systems that are more efficient with AC than DC and this is one reason why the AC is far more popular.