a.c. is current which changes direction and instantaneous value with time. Peak or r.m.s. values can be calculated if the other is known. Frequency can be determined from graphical data.
Most of our everyday uses of electricity are when electrons are moving in conductorA material which allows charge to move easily through it. 鈥 this is current flow as opposed to static electricity.
Direct current (d.c.) is a one-way flow of electronSubatomic particle, with a negative charge and a negligible mass relative to protons and neutrons. from negative to positive terminals of a power supply.
Alternating current (a.c.) is an oscillation of electrons or 'back and forward' movement.
One full cycle of alternating current is shown in the diagram below:
In the first half of the cycle the currentMoving electric charges, eg electrons moving through a metal wire. flow is in one direction. In the second half the current flow reverses.
Oscilloscopes are used to display a.c. waveforms. The y-axis plots the voltage across a componentWorking parts of a product or system.. The x-axis shows how this changes over time.
An oscilloscope trace allows us to determine two important quantities of an a.c. signal: frequency and peak voltage.
Question
Why is alternating current used so extensively around the world?
Transformers can increase and decrease voltageThe potential difference across a cell, electrical supply or electrical component. It is measured in volts (V). in a.c. supply networks. Using transformers reduces current flow in transmission lines and saves energy when supplying electricity over large distances.