This page is intended to give some independent information on the mechanics of turntable systems, indicating the known limits to performance where possible. A basic familiarity with algebra is plus some familiarity with electrical analogies of rotational dynamic systems is assumed. The analogies used are based on those developed by Harry Olson, see for instance his Dynamical Analogies (Van Nostrand 1943). Under this system moment of inertia is substituted by inductance and angular displacement is substituted by electrical charge (q). All other analogous quantities can be derived from these.