Abstract: A method and apparatus for measuring differences between forces, pressures, and combinations thereof. One or more force or pressure deformable members, preferably metal bellows, are internally connected by rigid linkage which is in turn connected to a component for translating force magnitude into corresponding electromagnetic signals. In an embodiment, the apparatus has a pressure chamber (40), an elastic vibrating member (50), an electromagnetic coil (60), a linkage (33), a rigid body (30), a body extension (35), and a bellows (22) defining in part a reference chamber (20). Bellows (22) is attached at bellows fixed end (23) to rigid body (30) and is deformable in response to a difference between a bellows internal reference pressure P.sub.0 and any pressure P.sub.1 external to bellows (22), such as in pressure chamber (40). Elastic vibrating member (50) is connected at a first end to linkage (33). Linkage (33) projects rigidly from an interior face of movable end (24).