Abstract: An electricity meter comprising an electrically-controlled electromechanical switch is disclosed. The electromechanical switch comprises a rotary actuator comprising a generally-cylindrical permanent magnet rotor having a central axis, a stator comprising a closed stator core and first and second opposite stator poles inwardly-projecting from the closed stator core towards the rotor and first and second coils wound around the first and second stator poles respectively. The electromechanical switch comprises a switch comprising at least one pair of first and second contacts wherein the first contact is movable. The electromechanical switch comprises mechanical linkage between the rotary actuator and the movable contact(s) configured such that rotation of the rotor from a first angular position to a second angular position causes the switch to be opened, and rotation from the second angular position to the first angular position causes the switch to be closed.

Abstract: An ultrasonic meter (28) for measuring a flow-rate of a fluid is described. The ultrasonic meter (28) includes a flow conduit (5) for the fluid. The flow conduit (5) extends along a first axis (6) between a first opening (7) and a second opening (8). The ultrasonic meter (28) also includes one or more pairs of ultrasonic transducers (2, 3). Each pair of ultrasonic transducers (2, 3) is configured to define a corresponding beam path (9) intersecting the flow conduit (5) within a measurement region (12) of the flow conduit (5). The measurement region (12) spans between a first position (z1) and a second position (z2) spaced apart along the first axis (6). One or more portions of the measurement region (12) which are outside of any of the one or more beam paths (9) correspond to non-sampled volumes (12b). The ultrasonic meter (28) also includes one or more protrusions (34) extending along the first axis (6).

Abstract: A method for an ultrasonic time-of-flight flow meter (1) includes driving an ultrasonic transducer (2, 3) using a first waveform (V1(t)) for a first duration (?t1), the first waveform (V1(t)) configured to cause oscillation (21) of the ultrasonic transducer (2, 3). The method also includes driving the ultrasonic transducer (2, 3) using a second waveform (V2(t)) for a second duration (?t2). There is a discontinuity between the first waveform (V1(t)) and the second waveform (V2(t)). The second waveform (V2(t)) and the second duration (?t2) are configured to maintain a voltage (VT(t)) across the ultrasonic transducer (2, 3) within a predetermined range (VH, VL).

Abstract: A solenoid actuator is described. The solenoid actuator comprises an armature, pole piece(s), electromagnet coil(s) arranged, in response to energization, to cause travel of the armature between first and second positions along a direction of travel, permanent magnet(s) positioned and orientated for latching the armature in at least the first position when the armature is in the first position and spring(s) arranged to bias the armature. The solenoid actuator can be operated to provide partial lift.

Abstract: A current sensor comprises a first component comprising plural coils. Each coil comprises one or more turns printed on at least one planar surface of a respective substrate, and the planes of the coils are parallel to one another and are perpendicular to a longitudinal axis of the first component. A second component comprises soft magnetic material and has first and second planar faces that are at opposite ends of the first component and are arranged perpendicularly to and are intersected by the longitudinal axis of the first component.

Abstract: A sensor for use in detecting a time-varying current in a conductor (106) comprises plural sets of two oppositely-configured sensor elements (104-1 . . . 104-6) arranged around a sensing volume having a central axis, the sensor elements (104-1A, 104-1B) of each set being provided substantially in a common plane that does not intersect the central axis, and each set having a different common plane, the sensor elements of each set being arranged such that a normal (N) of their common plane at a point between central parts of sensor elements lies on a plane (P) that is radial to the central axis of the sensing volume.

Abstract: A current sensor arrangement comprises plural sensor elements arranged around a center point, each of the sensor elements having a plane of zero sensitivity to uniform magnetic fields. A first one (202) of the sensor elements has a first angular separation (X1) relative to the center point from a second, adjacent sensor element (204) and a second angular separation (X2) relative to the center point from a third, adjacent sensor element (206). The first angular separation is less than the second angular separation. An intercept (I13) of the planes of the first and third sensor elements is located outside a triangle formed by the center point and the first and third sensor elements and an intercept (I12) of the planes of the first and second sensor elements is located inside a triangle formed by the center point and the first and second sensor elements.

Abstract: A current sensor comprises a first component comprising plural coils. Each coil comprises one or more turns printed on at least one planar surface of a respective substrate, and the planes of the coils are parallel to one another and are perpendicular to a longitudinal axis of the first component. A second component comprises soft magnetic material and has first and second planar faces that are at opposite ends of the first component and are arranged perpendicularly to and are intersected by the longitudinal axis of the first component.

Abstract: A system for processing a signal from a sensor is described. The system comprises an analog-to-digital converter. The system is configured to vary a sampling rate of said analog-to-digital converter dependent on an expected shape of the signal.

Abstract: An electrical current sensor and utility electricity meter, the current sensor comprising a &pgr; resistor shunt configuration, wherein the resistors comprise layered conductors at substantially equal temperatures to provide a zero temperature coefficient sensor. A fiscal electricity meter is described together with a four-layered current sensor fabricated using PCB techniques.

Abstract: A fiscal electricity meter is described for measuring the energy supplied to a load. The load current flows through the primary winding of a transformer and induces an EMF indicative of the current flowing in the secondary winding. The secondary winding comprises a sense coil, arranged to couple more strongly to the primary, and a cancellation coil which have equal and opposite turns area products so as to provide a null response to extraneous magnetic fields. The coils are arranged so that their magnetic axis are co-located and aligned together so that they also provide a null response to extraneous magnetic fields having a field gradient.