Abstract: A displacement-measuring transducer has a laminar member displaceable, for example under control of a vacuum actuator, within a housing containing respective pairs of coils spaced part in the displacement direction of the laminar member, which is provided with two apertures spaced apart in the said direction, such that the coupling between the coils of each pair is dependent upon the position of said apertures and, therefore, on the displacement of the laminar member.

Abstract: A comparator for comparing the relative magnitudes of first and second voltages and for providing a binary output indicative of which of the voltages is the greater. The voltages are applied sequentially to a capacitor during first and second periods respectively. An inverter has its input connected to the capacitor, and a voltage bias source applies a bias voltage to the input of the inverter in such a manner as to cause the output of the inverter to assume a predetermined voltage during the first period and a voltage either greater or less than the predetermined voltage during the second period, depending upon whether the first voltage is greater or less than the second voltage. A flip-flop is connected to the output of the inverter such as to be either set or reset in response to the output of the inverter being greater or less than the predetermined voltage during the second period.

Abstract: A displacement transducer suitable for monitoring the angular rotation of an internal combustion engine is provided. The transducer comprises a rotary disc having a castellated periphery and mounted for rotation with the engine. First and second coils are mounted such that upon operation of the engine the castellations of the disc interrupt the inductive coupling therebetween. The first coil is fed with an oscillatory electrical signal which induces in the second coil an output signal of a first peak amplitude during the interruptions produced by the castellations and of a second peak amplitude during periods between the interruptions. Thresholding circuitry responsive to the output signal produces a control signal which is indicative of the commencement and cessation of the interruptions. In accordance with one disclosed embodiment, the threshold circuitry includes a pair of inverters sharing the same thermal environment.

Abstract: The invention concerns an internal combustion engine provided with a vacuum sensor for monitoring the level of partial vacuum in the engine's inlet manifold, in order to provide an indication of engine load. during changes in engine load, the level of partial vacuum presented to the vacuum transducer is modified from that obtaining in the inlet manifold in order to improve the accuracy of the output of the transducer during changes of engine load.