Here are entered works about clocks equipped with mechanical organs. Works about clocks equipped with carillons or other chiming mechanisms are entered under the heading Chiming clocks.
Here are entered works on present-day calculators as well as on calculators and mechanical computers of pre-1945 vintage. Works on modern electronic computers first developed after 1945 are entered under Computers.
Here are entered works on electric generators, motors, transducers, sensing instruments, microphones, and similar devices, which convert electrical energy into mechanical energy, or the reverse, and which normally function as components of larger systems, e.g. electric power systems, information systems, control systems, etc.