Pickup cartridge  --  A device used with a turntable to convert mechanical variations into electrical impulses. There is a variety of ways whereby the motion of the stylus can be translated into an electrical signal. Most of these are grouped into the class known as magnetic, because they produce relative movement between a coil and magnetic field. They are velocity devices because the magnitude of the induced signal depends on the velocity of the stylus movement rather than its amplitude. But as tracing speed increases with amplitude so does the output signal. However, stylus velocity also increases with frequency, giving a rising treble response. This is the opposite of the recording cutter characteristic, but as that was modified by the RIAA curve, so also inversely must the response of the magnetic cartridge. At present the moving-magnet and moving-coil types are most in favour, but other types as well as non-magnetic varieties are in use.