PVC (Polyvinyl chloride) is extracted from the polymerization of vinyl chloride monomer. We can classify PVC into two large groups, rigid PVC and flexible PVC.

Rigid: used for the construction of tubes, pipes, containers, tool accessories, parts of parts, blinds, windows, etc.
Flexible: Corrugated tube, traffic signs as cones. irrigation hoses, curtains for refrigerators, footwear, medicine, etc.

This material begins to soften at 80 ° C and melt at 140 ° C. Thanks to these and other properties, PVC is a recyclable material.

Among the main characteristics of PVC we find:

• Different degree of hardness.
• Waterproof.
• It does not corrode.
• It is moldable if it is subjected to high temperatures.
• Good electrical insulator.
• It is a very resistant material.
• Stable and inert.
• Good mechanical and impact resistance.
• High resistance to abrasion.
• Strong and lightweight.
• Good thermal insulation.
• It is odorless, tasteless and harmless.

The impedance (Z) is a measure of opposition that a circuit to a current when a voltage is applied. The impedance extends the concept of resistance circuits alternating current (AC), and has both magnitude and phase, unlike resistance, which has only magnitude. When a circuit is powered with direct current (DC), there is no distinction between the impedance and resistance; the latter can be thought csa impedance with zero phase angle.

One hertz is one cycle per second, meaning repeating cycle as an event. For example, hertz is applied physics measuring the number of times for a second wave (either acoustic or electromagnetic) is repeated or can be applied, among other uses, to ocean waves that reach the Beach vibrations per second or a solid. The quantity that measures the frequency hertz is called,in this regard, the inverse of the period. One hertz is an oscillation frequency of suffering a particle over a period of one second.