Is alternating current better?
1 Answer
It depends on the use of the current.
Some devices can only be used with alternating current whilst others can only be used with direct current. So to speak of "better" is not strictly speaking accurate.
Computers, mobile phones (cell phones in US), tablets and anything else with a circuit board require direct current. Alternating current cannot be used to power those devices directly. In order to power/charge those devices the AC from the mains supply must first be converted to DC.
Desktop computers have a convertor built in. Laptops, mobile phones and tablets have a convertor in their chargers (the chargers then charge a battery in the device which provides DC).
Electric motors require AC current to work. DC will not power them. So in order to power a motor from a battery DC to AC conversion will need to take place first.
One device where it could be possible to discuss which is "better" is a light bulb. A bulb will work with both AC and DC. However, all that matters in a bulb's performance is the power supplied to the filament to heat it up. For a good brightness we would want to provide a high current and voltage to the bulb. In most domestic situations a very high power battery is not available, nor is it economical or practical. The most obvious source of enough power in a home is the mains supply, which happens to be AC.
One final consideration. Should the mains supply be AC or DC? For the mains AC is best for the following reasons:
1. Power stations produce AC electricity (because they use alternators).
2. National grids use transformers to reduce energy wastage in power lines (transformers only work with AC).
3. AC is fine for the most common uses of high power electricity in the home (electrical lighting and cooking).
