Applications and Limitations of Mechanical-Electrical Analogies, New and Old

The general problem of mechanical-electrical analogies is discussed. The advantages of Firestone's mobility system over the older analogy is clearly demonstrated especially when used with the powerful methods of circuit analysis presented. Torsional and geared, as well as linear systems are discussed. It is shown that the choice of analogy to be used is usually one of convenience, but that certain systems intrinsically make only one analogy possible. It is further shown that the use of a mechanical-electrical analogy in a system involving both electromagnetic and electrostatic coupling is fundamentally impossible as the resulting circuit could not satisfy Maxwell's equations.