Periodic Signals are signals that repeat themselves after a certain amount of time. More formally, a function

*f(t)*is periodic if

*f(t + T) = f(t)*for some

*T*and all

*t*. The classic example of a periodic function is

*sin(x)*since

*sin(x + 2 π) = sin(x)*. However, we do not restrict attention to sinusoidal functions.

### Sinusoid

The quintessential periodic waveform. These can be either Sine functions, or Cosine Functions.

### Square Wave

The square wave is exactly what it sounds like: a series of rectangular pulses spaced equidistant from each other, each with the same amplitude.

### Triangle Wave

The triangle wave is also exactly what it sounds like: a series of triangles. These triangles may touch each other, or there may be some space in between each wavelength.

Easy way to express

### Sinusoidal voltage is rms. Root Mean Sqaure

Periodic signal one that is repeated after certain amount of time.

single phase ac generation

# Electronics/Magnetic Field

The generation of AC electric power is commonly three phase, in which the waveforms of three supply conductors are offset from one another by 120°. The design of the power generators has three sets of coils placed 120 degrees apart rotating in a magnetic field. This creates three separate sine waves of electricity that are displaced from each other in time by 120 degrees of rotation (1/3 of a circle). Standard frequencies of rotation are either 50 Hertz (cycles per second) in Europe or 60 Hertz in North America.

Electric Maintenance Fundamentals - AC/DC Theory

When we can get electrons to flow away from their atom in a single direction we have electricity.

Silver , glass, aluminum good conductors.

Insulator plastic, dry wood, rubber

turning crank on generator forces electrons through conductor.