Original: A pickup device acts as a transducer that captures mechanical vibrations ( usually from suitably-equipped stringed instruments such as the electric guitar , electric bass guitar or electric violin ) and converts them to an electrical signal , which can be amplified and recorded .
Simplified: A pickup is a device that captures mechanical vibrations ( usually from stringed instruments like the electric guitar , electric bass guitar or electric violin ) and converts them to an electrical signal which can be amplified and recorded .