What is the different between electric, acoustic and classical guitar strings?

There are three main types of guitar strings: Electric, Acoustic and Classical..

Electric guitar strings
Usually Nickel-plated steel wound onto carbon steel, but sometimes stainless steel. Because the electric guitar pickup directly senses the vibration of the string magnetically, the strings must be made of ferrous metals - i.e. they must contain iron, which is magnetic.

Acoustic guitar strings (steel)
Most steel guitar strings are known as Bronze or Phosphor Bronze. Because the guitar does not rely on magnetic pick-ups non-ferrous metals may be used. The core wire is still made of steel (hence 'steel string' guitars), but the outer winding on the 'wound' strings is made of bronze.

Nylon guitar strings (classical or Spanish guitar)
Guitar strings were originally made from animal gut, but in 1969 Augustine created the world's first synthetic guitar strings, made from Nylon. All classical guitar strings are now made from nylon. The bass strings are wound with metal wire however, the same as other types of strings. These fine wire wrappings are made from bronze, silver or other metals.

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