Passive mass-spring type of sensing device having electronic damping

In a device including means for producing a magnetic field and a single electrically conductive coil having a given impedance disposed within said magnetic field in a way which results in relative movement between the coil and field corresponding to a particular parameter being monitored whereby to produce a voltage signal which also corresponds to said parameter, a circuit arrangement for damping said relative movement, comprising means connected with said coil for providing a closed electrical circuit including the coil such that the relative velocity between the coil and field as a result of said movement causes a current to be produced in said circuit including said single coil and to flow through said single coil in a way which produces a force, proportionate in magnitude to said current, opposing said movement whereby to dampen said movement, said circuit providing means also including mean for maintaining said voltage signal at a measurable value while, at the same time, reducing the total effective impedance of said closed circuit including said single coil below the given impedance of said coil whereby to increase the magnitude of said current and therefore its associated damping force to a greater value than would be possible merely by shorting together the ends of the coil.