I understand that cables have capacity and inductance, is this caused by the existence, of more than one conducting wire (or element) in the cable? so for instance in an electric guitar cable, the wire with the signal becomes a capacitor because it runs parallell to its shield? and if so, how does it become an inductor? presumably because it coils to some extent?

Thanks for your help!

julio

 

Any conductor carrying a current has an associated magnetic field due to the current flow. By definition the conductor's inductance is the magnetic flux linkages formed with the conductor per unit current flowing in the conductor.

Any length of conductor therefore has a self inductance.

This is often undesirable for optimum circuit performance. If the positive and negative supply conductors in a circuit loop are laid adjacent to each other (or twisted together) the individual conductor magnetic fields will tend to cancel [the currents are flowing in opposite directions] and this tends to reduce the overall circuit inductance.