Practical Electronics/Sources

Sources that provide Voltage or Current to provide electricity for electrical devices to operate.
 * Simple_dc_power_supply_schematic.png

Voltage Sources
There are two Voltage Sources generally used in any applications namely AC and DC Voltage Source:

DC Electricity
DC stands for Direct Current. Voltage source that has constant voltage that does not change with time and can be expressed mathematically
 * v = V

DC Voltage sources are found in Batteries,

AC Electricity
AC stands for Alternating Current. Voltage source that has current amplitude varies sinusoidally with time and can be expressed mathematically
 * v = Vp Sin wt
 * Vp The highest value of the voltage also called Peak Voltage measured in Volt (v)
 * t - time measured in second (s)
 * w - Angular Frequency . w = 2πf = $$\frac{2\pi}{t}$$

AC Voltage source are generated from AC generators.

Current Sources
Current sources act in a similar manner to voltage sources, except that they try and maintain a constant current. Current sources are mainly constant current devices, meaning that they have a set value that they try and maintain, but also exist as variable devices, such as in transistor models.