Electrical energy is distributed as alternating current because AC voltage may be increased or decreased with a transformer. This allows the power to be transmitted through power lines efficiently at high voltage, which reduces the energy lost as heat due to resistance of the wire, and transformed to a lower, safer, voltage for . Transmission, distribution. Direct Current (DC) - learn.
In direct current (DC), the electric charge (current) only flows in one direction. Electric charge in alternating current ( AC ), on the other han changes direction periodically.
The voltage in AC circuits also periodically reverses because the current changes direction. In our daily life we all keep hearing terms like 230V AC power plug, AC to DC power supply and 1. In our tutorial about the AC Waveform we looked briefly at the RMS Voltage value of a sinusoidal waveform and said that this RMS value gives the same heating effect as an equivalent DC power and in this tutorial we will expand on this theory a little more by looking at RMS voltages and currents in more detail. Likewise, any part of the waveform which lies below the horizontal zero axis represents a voltage or current flowing in the opposite direction to the first.