The transmission of electrical energy requires very high voltages (for a given load, the higher the supply voltage, the lower the load current). To increase/reduce these voltages, you need Transformers. Transformers are AC machines; they do not work with DC.
It blocks direct electrical current allowing alternating current to pass
Electrical (alternating current)
Three-phase 408V systems typically use alternating current (AC).
In North America the electrical system is alternating current at a frequency of 60 Hertz. Europe and the UK use alternating current at a frequency of 50 Hertz. Direct current systems are obsolete because of the inability to transmit the voltage over long distances.
Electric current from a generating plant is typically alternating current (AC), which flows back and forth in a rapid and regular manner. This AC current is then transmitted through power lines to homes and businesses for use in electrical appliances and devices.
He was an inventor in electric things, mechanical engineer, physicist, and futurist best known for his contributions to the design of the modern alternating current (AC) electrical supply system.
alternating current
Nikola Tesla was the inventor of the alternating current light and power system in use all over the world today.
Nikola Tesla invented the alternating current (AC) electricity system, which is still the basis for electrical power distribution today. He also contributed to the development of the radio and wireless communication technologies that we use in modern telecommunications.
a high power, often class C amplifier.
The main division is between alternating current (AC) and direct current (DC). AC is universal now for domestic and industrial supply, but DC used to be used in some places in the early part of last century. Automobiles use DC at 12V which is I think universal now. AC in domestic use can be at 50Hz (Europe and many other places) or 60Hz (North America), and can be at either 240V or 120V.
A rectifier on a motorcycle converts alternating current (AC) generated by the alternator into direct current (DC) to charge the battery and power the electrical system. This ensures a steady supply of power to the motorcycle's electrical components.