Abstract: According to one embodiment, a sensor includes a detection device and a circuit portion. The detection device includes a first detection portion and a second detection portion. The first detection portion includes a first detection element. The first detection element includes a first conductive member and a first detection member. The second detection portion includes a second detection element. The second detection element includes a second conductive member and a second detection member. The circuit portion is configured to execute a first detection portion operation for outputting a first detection result corresponding to a first detection value based on the first detection member when a first current is supplied to the first conductive member. In a case where a first evaluation value is not within a first range, the circuit portion is configured to execute a second detection portion operation by the second detection portion.

Abstract: According to one embodiment, a sensor includes a detection device, a switch circuit, and a detection circuit. The detection device includes a first detection section and a second detection section. The first detection section includes a first detection element. The first detection element includes a first conductive member and a first resistance member. The second detection section includes a second detection element. The second detection element includes a second conductive member and a second resistance member. In a first operation, the switch circuit is configured to supply a first current to the first conductive member and not to supply the first current to the second conductive member, and the detection circuit is configured to output a first signal corresponding to a difference between a first electrical resistance of the first resistance member and a second electrical resistance of the second resistance member.

Abstract: A ferrite for magnetostrictrive vibrators is produced by the simple process of press forming a preformed structure formed from starting powder of magnetite or a mixture of magnetite and ferric oxide, said powder having an average particle size d (.mu.) of from 0.02 to 5.0 .mu., sintering this structure in an atmosphere wherein the partial pressure of oxygen is from 10.sup.-1 to 10.sup.-11 atmosphere at a temperature of from 1,000.degree. to 1,350.degree. C. and which will meet the requirement:140 log d+1,305.gtoreq.T(.degree.C.).gtoreq.160 log d+1,180and thereafter cooling the structure thus sintered to room temperature at a cooling rate m (.degree.C./min.) <0.5f where f(KHz) is a corresponding resonance frequency thereby to produce a macroscopically homogeneous ferrite structure containing as its principal constituent a sintered magnetite having an oxygen/iron (O/Fe) atomic ratio of 4.0/3<0/Fe<4.1/3, and a density of at least 90% of the theoretical density.

Abstract: A method for generating magnetostrictive vibration which comprises:Providing a vibrator element comprising a sintered structure of magnetite having an oxygen/iron (O/Fe) atomic ratio within the range of 4.0/3 to 4.1/3, a specific resistance of not lower than 0.1 ohm cm, and a positive static magnetostriction and containing in its sintered state at least one additive element selected from the group consisting of cobalt, calcium, titanium, silicon, boron, and sodium; andApplying an alternative magnetic field to the vibrator element.There is also provided an improved magnetostrictive vibrator element for use in the above method, which comprises:The above-mentioned sintered structure, andFixing means for applying a compressing force of 30 to 1800 Kg/cm.sup.2 to opposite ends of the sintered structure in the direction of the principal vibration thereof.