AC Circuit Theory: What is AC and How its Generated

An electrical circuit is a complete conductive path through which electrons flow from the source to the load and back to the source. The direction and magnitude of the electrons flow however depend on the kind of source. In Electrical Engineering, there are basically two types of voltage or current (Electrical Energy) source which defines the kind of circuit and they are; Alternating Current (or voltage) and Direct Current.

For the next couple of posts, we will be focusing on the Alternating current, and move through topics ranging from what is Alternating current to AC wave forms and so on.

AC Circuits

AC circuits as the name (Alternating Current) implies are simply circuits powered by an Alternating Source, either voltage or current. An Alternating Current or Voltage, is one in which the value of either the voltage or the current varies about a particular mean value and reverses direction periodically.

Most present day household and industrial Appliances and systems are powered using alternating current. All DC based plugged in appliances and rechargeable battery based devices technically run on Alternating current as they all use some form of DC power derived from AC for either charging of their batteries or powering of the system.  Thus Alternating current is the form via which power is delivered at the mains.

The Alternating circuit came into being in the 1980s when Tesla decided to solve the long range incapability of the Thomas Edison’s DC generators. He sought a way of transferring electricity at a high voltage and then employ the use of transformers to step it either up or down as may be needed for distribution and was thus able to minimize power loss across a great distance which was the main problem of Direct Current at the time.

Alternating Current VS Direct Current (AC vs DC)

AC and DC differ in several ways from generation to transmission, and distribution, but for the sake of simplicity, we will keep the comparison to their characteristics for this post.

The major difference between the AC and DC, which is also the cause of their different characteristics, is the direction of flow of electric energy. In DC, Electrons flow steadily in a single direction or forward, while in AC, electrons alternate their direction of flow in periodic intervals. This also leads to alternation in the voltage level as it switches along from positive to negative in line with the current.

DC Current Flowing in one Direction

AC Current alternating at Intervals