Sinusoidal signals is a type of alternating waveform available from commercial supplies. The term alternating indicates only that the waveform alternates between two prescribed levels in a set time sequence.
Sinusoidal ac voltages are available from a variety of sources. The most common source is the typical home outlet, which provides an ac voltage that originates at a power plant.
Sinusoidal ac voltages with characteristics that can be controlled by the user are available from function generators. By setting it to different values, one can make available sinusoidal voltages of different peak values and different repetition rates. The function generator plays an integral role in the investigation of the variety of theorems, method of analysis, etc.