An Acoustic Electric Guitar is an acoustic guitar fitted with pickusp, a microphone or transducers.
In acoustic-electric guitar (s), the transducers and microphones are
always used because conventional pickups are not capable of picking up
vibrations of non-magnetic materials. The design is distinct from a semi-acoustic guitar, which is an electric guitar but with the addition of sound chambers within the guitar body. Usually, acoustic-electric guitar (s) are fitted with piezoelectric pickups, and hence require a preamplifier incorporated into the guitar body to amplify the signal before it travels to the main guitar amplifier.
These preamps may also come with tone controls of varying types, but
usually equalizers with up to six frequency bands are used. They are
also referred to as a "plug-in acoustic guitar", due to their ability to
simply "plug in" to a speaker system without the need for microphones.
Acoustic Electric Guitar (s) are commonly used in folk and sometimes classical music as acoustic electric guitar (s) possess the sound of an acoustic guitar but more volume if plugged into a speaker system.