Abstract: Systems and methods are provided for depositing solder in a first pattern over a first bonding pad on the substrate; depositing solder in a second pattern over a second bonding pad on the substrate, wherein the second pattern defines a larger area than the first pattern; placing the electronic device on the substrate such that pads on the electronic device are aligned with the first and second bonding pads; and reflowing the solder between the pads on the electronic device and the first and second bonding pads, causing the solder deposited on the first bonding pad to form a first solder joint and the solder deposited on the second bonding pad to form a second solder joint. The second solder joint is larger than the first solder joint causing the electronic device to be attached at an angle relative to the substrate.

Abstract: Systems and methods are provided for depositing solder in a first pattern over a first bonding pad on the substrate; depositing solder in a second pattern over a second bonding pad on the substrate, wherein the second pattern defines a larger area than the first pattern; placing the electronic device on the substrate such that pads on the electronic device are aligned with the first and second bonding pads; and reflowing the solder between the pads on the electronic device and the first and second bonding pads, causing the solder deposited on the first bonding pad to form a first solder joint and the solder deposited on the second bonding pad to form a second solder joint. The second solder joint is larger than the first solder joint causing the electronic device to be attached at an angle relative to the substrate.

Abstract: The invention is directed to a waveguide termination comprising a waveguide having an end and a window through which light can pass. The end of the waveguide has an elliptical face and the elliptical face reflects light between the waveguide and the window. Preferably the optical waveguide is an optical fibre.

Abstract: A baffle located within a receptacle for liquid to control surging particularly suitable for use with firefighting vehicles having a water supply wherein the baffle is formed of polymeric intersecting longitudinal and transverse plate members having intermeshing slots and reinforcing inserts located in each plate member receive the end region of the intersecting plate member to support the end regions against deformation and displacement.

Abstract: A system for regulating the idling speed of an internal combustion engine comprises a circuit for generating the ignition spark, when the engine is idling, upon expiry of a predetermined time delay from an initial crankshaft position, which circuit is enabled only after the crankshaft has reached a first limiting position, and enforced when the crankshaft reaches a second limiting position if the time delay has not expired. The spark timing therefore varies smoothly with speed between the first and second limiting positions of the crankshaft, but being retarded to the second limiting position for large over-speed errors or advanced to the first limiting position for large under-speed errors. It also reverts to the second limiting position for speeds below half normal idling speeds (cranking speeds).

Abstract: A mechanically timed ignition system for an internal combustion engine has a variable reluctance transducer mechanically operated by the engine to produce an output waveform having zero crossings coinciding with the desired instants of sparks. A comparator means at the input of an integrated ignition control circuit is connected to a winding of the transducer. The i.c. output point, which controls a semiconductor switch connecting an ignition coil across a supply, is connected by a C-R feedback path to the input of the comparator means, to provide transient positive feedback, which is effective at cranking speed to provide improved rejection of low level audio frequency interference signals.

Abstract: An internal combustion engine ignition control includes a variable reluctance pick-up with a winding providing signals to an integrator the output of which controls an ignition switching circuit. The ignition switching circuit includes a current limiter circuit which operates to limit the coil current at a maximum level until the instant of ignition. A capacitor is charged and discharged under the control of the current limiter circuit so that the voltage on it depends on the ratio of the time for which the current limiter circuit is in operation to the ignition cycle duration. An active clamping circuit operates to override the integrator under the control of this capacitor so as to apply a variable preconditioning bias to the output of the integrator which has the effect of varying the instant at which the coil current is switched on. Closed loop dwell control is thus provided in a simple and convenient manner.

Abstract: An ignition system transducer comprising a ferro-magnetic disc mounted on a distributor shaft and having four pairs of protuberances, the spacing of the two protuberances of each pair corresponding to the maximum and minimum spark advance positions. Rotation of the protuberances about the distributor shaft is detected by a first variable reluctance pick-up mounted in a fixed position, and by a second variable reluctance pickup movable in accordance with an engine load sensor. These two pick-ups in conjunction with signal generators produced a fixed phase waveform, and a variable phase waveform which varies in accordance with engine load.

Abstract: An ignition system comprises a ferro-magnetic disc mounted on the distributor shaft and provided with four pairs of protuberances, the spacing of the two protuberances of each pair corresponding to maximum and minimum spark advance positions. The protuberances are detected by a first variable reluctance pick-up of fixed position and a second variable reluctance pick-up angularly movable by an engine load sensor. The two pick-ups, are connected respectively to two signal generators which produce a rectangular waveform of fixed phase and a rectangular waveform, the phase of which varies in accordance with engine load. The two waveforms have the same frequency. A function timing circuit responsive to both waveforms calculates engine speed, engine load and crank-shaft position and from these produces a trigger signal for each ignition spark. Further circuitry responsive to the trigger signals drives the ignition coil.

Abstract: A control circuit for an electromagnet includes a main current control element in series with the electromagnet winding and controlled so as to switch on and pass a "pull-in" current for an initial period and to control the current to a lower "hold" level during a subsequent period. A capacitor is connected in series with a diode and a transistor across the winding and the transistor is controlled to switch on during the change from "pull-in" to "hold" so that the capacitor is charged up during this change. A second transistor is connected in series with a second diode to permit reverse current flow from the capacitor to the winding during switch-off to hasten collapse of the flux in the winding and overcome the drop-out delaying effect of eddy currents in the electromagnet core.

Abstract: A transducer includes a winding in a magnetic circuit including a magnet, a pole-piece and a disc which has pairs of protuberances in its periphery, each pair being connected by a web of lesser radial distance from the disc axis than the peaks of the protuberances. The winding is connected in a discriminating circuit including an integrator which integrates the winding output, and a zero crossing detector. An output circuit receives signals from the integrator and the zero crossing detector and produces an output signal for the whole period during which the web between two protuberances is passing the pole piece.

Abstract: A combined ignition control and injection valve operating circuit has an inductor connected in (series or) parallel with the ignition coil so that it carries current whenever an output transistor of an ignition control circuit is on.A thyristor connects the inductor to an energy storage capacitor and turns on each time the transistor turns off to create an ignition spark. The capacitor is thus charged up and the stored energy is discharged through a triac into an injection valve solenoid to speed up current growth in the latter on each energization thereof.

Abstract: A control circuit for an electromagnet includes a high voltage converter with a main energy storage element on which is stored a voltage higher than the supply voltage. A switch element connects this main storage element to the electromagnet and to an inductor by way of which energy is transferred to a secondary energy storage element which is used at the end of the electromagnet energization period to cause rapid collapse of the electromagnet flux.

Abstract: An electromagnet control circuit includes a first switching transistor which is connected in series with the electromagnet across a low voltage supply. A second switching transistor is connected to provide a high voltage supply to the electromagnet at switch-on. An inductor is connected by transistors to the low voltage supply and is supplied with current while the first switching transistor is on. At switch-off a diode interconnecting the electromagnet 10 and the inductor allows the inductor current to be diverted through the electromagnet to provide rapid flux decay in the latter.

Abstract: An internal combustion engine function control system, for example a spark ignition control system, comprising first and second pulse generating means driven by the engine. The first pulse generating means produces a train of pulses at a first frequency equal to the frequency of the required function and the second pulse generating means produces a train of pulses at a second frequency which is a multiple of the first frequency. Engine parameter sensitive means are provided for varying the phase of the second pulse train relative to that of the first pulse train between limits such that the combined ordinal succession of the pulses is maintained constant. The system further includes function timing means for causing triggering of an output circuit at the end of a delay following a pulse from said first pulse generating means.

Abstract: An internal combustion engine spark ignition system is provided which ensures that sparks are inhibited if the engine temperature exceeds a maximum safe level. The ignition circuit includes an input transistor which is switched on and off by an engine shaft transducer. The input transistor controls charging and discharging of a capacitor the voltage on which determines whether switching of the input transistor causes a spark to be produced via an output amplifier and ignition coil. A temperature sensing element determines both the rate at which the capacitor can charge and the final voltage to which it can be charged.

Abstract: A vehicle tire pressure warning system includes a rotating assembly and a non-rotating assembly. The non-rotating assembly includes a magnet and a pick-up coil. The rotating assembly includes a series circuit comprising a coil, a magnetically operated switch and a pressure actuated switch which is closed when the tire pressure is adequate. The magnetic switch is closed periodically by the magnet and current is induced in the coil. When the magnetic switch re-opens the coil is coupled to the pick-up coil and the flux collapse in the coil causes a signal to be induced in the pick-up coil. The absence of such a signal indicates that the tire pressure is too low and is detected by a counter system for each wheel which counts the number of pulses from all the wheels between pulses from the associated wheel.

Abstract: An internal combustion engine spark ignition system includes a transducer and a transducer circuit which coact to produce a rectangular pulse for each spark required. The leading edge of this pulse controls an input transistor which controls an output transistor through an intermediate transistor. The output transistor in turn controls an ignition circuit controlling the current through an ignition coil. The coupling between the intermediate and output transistors includes a resistance chain to points in which two timing capacitors are connected. At high speeds the circuit provides a fixed coil current duty cycle with a relatively short off time, whereas, at low speeds the duty cycle is determined by the length of the pulses from the transducer circuit giving a relatively long off time.

Abstract: A pulse waveform recognition circuit includes an input stage consisting of a tuned circuit tuned to approximately the frequency of a sinusoid to half-waves of which the pulses to be recognized approximate. A transistor is biased to conduct weakly and has its base coupled to the tuned circuit so as to be turned on by a pulse within the band width of the tuned circuit. The transistor drives a monostable multi-vibrator with a frequency dependent feedback circuit which causes the reversion time of the multi-vibrator to decrease as the frequency of triggering increases and which also increases the threshold voltage required to trigger the monostable circuit as this frequency increases. The circuit is used in an ignition system for an i.c. engine.