818,065. Semi-conductor devices. SIEMENSSCHUCKERTWERKE A.G. Nov. 24, 1955 [Nov. 26, 1954], No. 33722/55. Class 37. A Hall effect device comprises a semi-conductor member with asymmetrical Hall electrodes such that a voltage appears between these electrodes when primary current is flowing but no magnetic field is applied, and means for applying a magnetic field of such magnitude that the Hall potential is reduced to zero or doubled, depending upon the direction of the field. The device may be utilized in switching, control or measuring circuits. Fig. 2 shows a semi-conductor body 1 having primary electrodes 2 and 3, and asymmetrical Hall electrodes 4 and 5 the output from which is applied to a measuring instrument 6. Fig. 3 shows an arrangement comprising three Hall electrodes the initial voltage between electrodes 14 and 15, and 16 and 14 being arranged to be zero and doubled respectively or vice versa according to whether the magnetic field is applied in one or the opposite direction. The magnetic field can thus be used to switch the output to either of electrodes 15 and 16. Other arrangements are described involving more than three Hall electrodes at least two of which are positioned asymmetrically, for switching or control purposes. The relative position of one or more of the electrodes may be made adjustable. The semi-conductor material may consist of Am Bv compounds such as In Sb or In As. Specifications 719,873, 763,348, 797,505 and 802,687 are referred to,

819,494. Etectric indicating systems. KELVIN & HUGHES Ltd. July 26, 1957 [Aug. 8, 1956], No. 24330/56. Addition to 788,544. Class 40 (1). Apparatus for measuring the rotation of a compass magnet 11 relative to a craft on which it is mounted comprises a semi-conductor crystal 10 mounted coaxially with the magnet and in its magnetic field, fed with A.C. along its horizontal axis 12, 13 so that any angular displacement of this axis relative to the horizontal axis of the magnet produces a P.D. across the vertical axis 17, 18 by the Hall effect, which is fed to a motor 22 to realign the axes of the crystal 10 and the magnet 11. The rotation may be telemetered via a known transmitter 26 to remote receivers.

953,594. Semi-conductor pulse circuits. PHILIPS ELECTRICAL INDUSTRIES Ltd. Oct. 6, 1961 [Oct. 11, 1960], No. 36025/61. Heading H3T. [Also in Division G4] A counter constructed from photoconductive and electroluminescent devices is shown in Fig. 3. The counter is primed by closing switch S, whereupon a flash of light from lamp NI illuminates photoconductor 20 and electroluminescent device 21 is energized from terminals 18, device 21 creating a holding circuit for itself by illuminating a photoconductor 22. Device 21 also primes the first stage of the counter proper by illuminating photoconductor 24. A pulse applied to terminals 38 energizes an electroluminescent strip 19 which is common to all stages of the counter, and device 25 is then energized through a further photoconductor 40 associated with strip 19. Device 25 creates a holding circuit for itself through photoconductor 26, extinguishes device 21 by creating a shunt path through a photoconductor 23, and primes the next stage 29 by illuminating photoconductor 28. The following stages operate in a similar manner. The counter may be used to control a stepvoltage generator, Fig. 1, forming a balancing voltage source in an analogue-to-digital converter. The unknown voltage is applied at X, and devices 23, 25, 29 . . . of Fig. 3 are represented in Fig. 1 by light sources L 0 -L 9 . Initially L 0 is energized and photoconductor R 0 supplies a balancing voltage of 0.1 volts from a 1-volt source B 1 . Assuming an input at X of 0.86 volts, difference amplifier M energizes a lamp A1 which in turn controls a relaxation oscillator, Fig. 2 (not shown) supplying pulses to terminals 38, Fig. 3. Sources L 0 -L 8 are energized in sequence by the counter to produce an increasing step voltage until the input X is exceeded. Amplifier M then extinguishes A1 and lights A2, the latter controlling a further pulse source and counter including electroluminescent devices L 0 1-L 9 1. Devices L 9 1- L 6 1 are energized in turn to reduce the balancing voltage in steps of 0.01 volts until equality is attained.

1,004,738. Semi-conductor devices. APPLEBY & IRELAND Ltd. Aug. 7, 1963 [May 8, 1962], No. 17717/62. Heading H1K. A thermocouple is produced by causing the ends of a pair of wires projecting from the end of a metallic sheath, through which they pass and from which they are insulated, to touch one another and then uniting them by electron beam welding. As shown, Fig. 2, a thermocouple cable comprises two conductors 12, 13 of dissimilar metals, supported and insulated by a packing of metalli coxide 14, contained in a stainless steel sheath 11. The cable is drawn thro ugh a die to the required size and one end is inserted in a bore in a bush 21 and stripped to expose the conductors. The cable is mounted in a vacuum chamber and an electron beam 15 is used to weld sheath 11 to bush 21. As shown, Fig. 5, the ends of the conductors are bent into contact and then welded together, a ferrule 17 of Iconel (Registered Trade Mark) or stainless steel is welded to the sheath at 18, and the assembly is sealed by welding a plug 19 into the end of ferrule 17, all the joints being made by electron beam welding. Ferrule 17 may be filled with insulating material before inserting plug 19. In use the flange 22 of bush 21 may be welded to the casing of the apparatus. Specification 940,850 is referred to.

943,550. Measuring electrically. GAS COUNCIL. Dec. 8, 1960 [Dec. 8,1959], No. 41725/59. Heading G1N. [Also in Division B1] A thermal conductivity gas/vapour detector assembly comprises a block of material having good thermal conductivity through which block are disposed at least three separate passages for gas or vapour, each passage having disposed therein a thermistor as hereunder defined. The preferred construction comprises a brass block with cylindrical gas passages. The individual cells are connected in series by tubes packed with chromatographic absorbent. The term Thermistor is defined as a temperature sensitive device comprising a semi-conductor,the electrical resistance of which decreases rapidly with an increase in temperature. The invention is particularly described with reference to 3 drawings (only one shown) and includes the detector block 40 housing thermistors 45, 48, 50, 53, 54, a multiple volume gas burette 58-63 with means 65 to fill, purge and measure sample pressure 66, a plurality of packed columns 47, 49, 51, 52 and associated carrier gas flow controls 41, 42, 43, 55, 56, 57. A Table shows separations effected on various column packings using argon or hydrogen as carrier gases. The difference in thermal conductivity of the gas or vapour passing through the detector is measured by a circuit not detailed in the Specification. Specification 777, 233 is referred to.

854,204. Measuring colour temperatures. SIEMENS & HALSKE A. G. July 25, 1957 [July 25, 1956], No. 23662/57. Class 40(3). [Also in Group XX] In an instrument 2 for measuring the colour temperature of a body 1, in which the rays are divided according to their wavelength to fall on two detectors 10, 12, the division is effected by an inclined plate 7 made of an electrical semi-conductor such as germanium which reflects and transmits different wavelengths. A second different semi-conductor plate 11 may be added and either the transmitted or reflected rays detected. In a modification the inclined plate 7 is a semi-transparent mirror and a semi-conductor plate is inserted in one or both ray paths. The detectors may be thermo-couples or photocells. Reference has been directed by the Comptroller to Specification 803,347.

1,211,195. Magnetic switches. G.S.M. ELECTRICAL CONTROLS Ltd. 29 Nov., 1967 [31 Aug., 1966], No. 38770/66. Heading H1N. [Also in Division G1] A movable-magnet float switch has a sealed magnetic reed contact device 50 influenced by a magnet 54 which is moved about its pivot 58 by a magnet moved by a float (Fig. 1, not shown), so that the magnet 54 is moved in one direction due to the proximity of one pole of the float magnet and in the other direction due to the proximity of the other pole of the float magnet. The magnet 54 is retained in its extreme positions by its attraction to steel split pins 64, 66 one of which may be omitted if the assembly is mounted so that the magnet 54 is gravity biased to one position. A plurality of such assemblies may be operated by a common float magnet (Fig. 1). The reed contact device may be replaced by a magnetically sensitive semi-conductor or resistor (not shown).

Disclosed is a power meter applied to a bicycle or an auxiliary power bicycle, comprising: a central shaft (2), wherein one end of the central shaft (2) is connected to a right crank, and the other end of the central shaft (2) is connected to a left crank (2-3), the right crank being fixedly connected to a crankset; a torque collection sleeve (3), wherein the torque collection sleeve (3) is inserted into the central shaft (2), and two ends of the torque collection sleeve (3) are closely attached to the central shaft (2); a strain sensing patch (3-3) installed on a surface of the torque collection sleeve (3); and a power pen (4), wherein the power pen (4) is inserted into the torque collection sleeve (3), and the power pen (4) is used for processing and sending out signals outputted by the strain sensing patch (3-3). The power meter is convenient to install and is capable of accurately measuring the pedal force of a left foot. Compteur de puissance appliqué à une bicyclette ou à une bicyclette à puissance auxiliaire, comprenant : un arbre central (2), une première extrémité de l'arbre central (2) étant reliée à une manivelle droite, et l'autre extrémité de l'arbre central (2) étant reliée à une manivelle gauche (2-3), la manivelle droite étant reliée à demeure à un pédalier; un manchon de collecte de couple (3), le manchon de collecte de couple (3) étant introduit dans l'arbre central (2), et deux extrémités du manchon de collecte de couple (3) étant étroitement fixées à l'arbre central (2); un patch de détection de contrainte (3-3) installé sur une surface du manchon de collecte de couple (3); et un stylo d'alimentation (4), le stylo d'alimentation (4) étant introduit dans le manchon de collecte de couple (3), et le stylo d'alimentation (4) étant utilisé pour traiter et envoyer des signaux émis par le patch de détection de contrainte (3-3). Le compteur de puissance est pratique à installer et peut mesurer avec précision la force de pédalage d'un pied gauche. 一种应用于自行车或辅助动力自行车的功率计，包括：中轴（2），中轴（2）的一端与右曲柄相连接，中轴（2）的另一端与左曲柄（2-3）相连接，右曲柄上固定连接齿盘相连；力矩采集套（3），力矩采集套（3）插入中轴（2）内，力矩采集套（3）两端与中轴（2）紧密贴合；力矩采集套（3）表面安装有应变传感贴片（3-3）；功率笔（4），功率笔（4）插入力矩采集套（3）内；功率笔（4）将应变传感贴片（3-3）输出的信号处理发送出去。该功率计安装方便，并且能够准确的测出左脚的踩踏力。