Page 319 - Mechanical Engineers' Handbook (Volume 2)

310 Mathematical Models of Dynamic Physical Systems

Figure 4b Examples of transformers and transducers: pure mechanical transformers and transforming
transducers. 2

(electrical to mechanical rotation and vice versa). Examples of gyrating transducers are the
piston-and-cylinder (fluid to mechanical) and piezoelectric crystals (mechanical to electrical).
More complex systems may have a large number of energy ports. A common six-
terminal or three-port element called a modulator is depicted in Fig. 5. The flow of energy
between ports a and b is controlled by the energy input at the modulating port c. Such
devices inherently dissipate energy, since