Conditioners specifically work to smooth the sinusoidal A.C. wave form and maintain a constant voltage over varying loads.
Voltage spikes are most common during electrical storms or malfunctions in the main power lines.
The surge protector stops the flow of electricity from reaching a machine by shutting off the power source.
For example, if the application will be a home theater system, the noise suppression rating listed in the technical specifications of the power conditioner will be very important.
Units may be small enough to mount on a printed circuit board or large enough to protect an entire factory.
Ideally electric power would be supplied as a sine wave with the amplitude and frequency given by national standards (in the case of mains) or system specifications (in the case of a power feed not directly attached to the mains) with an impedance of zero ohms at all frequencies.