Abstract: In a magnetic-tape recorder, tension rollers positioned before and after the tape heads in the tape path have an outer layer of a polyurethane elastomer to absorb vibration of the tape and reduce flutter. Grooves in the elastomer layer enable the effective resilience of the elastomer to be reduced below the bulk value.

Abstract: Directional relay and method for monitoring at least one A.C. power transmission line to determine the position of a fault on the line with respect to a measurement location thereon.According to a representative embodiment characteristic parameters, typically the respective phases, of a first signal representing the difference of complex voltages after and before the occurrence of the fault and of a second signal representing the line current after the occurrence of the fault, are compared, the result of the comparison providing the desired indication.

Abstract: An electronic multiplying circuit, primarily intended for use in an electronic watthour meter, comprises a variable-transconductance multiplier of the type comprising two emitter-coupled pairs of transistors, the collectors of one pair being cross-coupled with the collectors of the other pair. In order to permit the effective polarity of one of the input signals to the multiplier to be reversed from time to time for drift correction purposes, this input signal is applied to a semiconductor switching circuit, which applies it alternately to the respective bases of a further emitter-coupled pair of transistors. The collectors of the transistors of this further pair are connected in series with the coupled emitters of respective ones of the emitter-coupled pairs in the variable-transconductance multiplier.

Abstract: A remotely-controllable relay which is controlled by 175 Hz ripple voltage superimposed on the mains supply voltage in an electric-power distribution network contains an oscillator generating a signal at 173 Hz. This is mixed with the network voltage so that, when ripple voltage is present, a beat note at a frequency of 2 to 3 Hz is generated. This beat note is separated from the unwanted signals, such as the mains supply voltage, by a third order active low-pass filter to control operation of the relay. A similar technique provides simplified detection of output signals from correlation-type filters.

Abstract: According to a representative embodiment of the invention, a parallel line printer such as a thermal printer is provided having a parallel printing head with a plurality of printing elements arranged to extend across the width of a paper strip. Electrical signals representative of characters to be printed can be stored in a storage device having a capacity corresponding to a full line of characters, and a print control logic is operative to cause the printing head to print up to a full line of characters simultaneously, or substantially so, in response to a print command. Means are provided to permit printing to be resumed on a line already containing characters printed in response to certain print commands. In the case when the paper is typically moved forward after one line has received print, means are provided to return such line back under the printing head if printing must resume on such line.

Abstract: An emulsifying system for mixing accurate ratios of two or more liquids to form an emulsion. The liquids are preferably, but not exclusively, water and oil. A supply circuit delivers accurate mixtures of the two or more liquids. An emulsifier emulsifies the mixture to form an emulsion. A container stores a quantity of the emulsion that may vary between predetermined limits and an output circuit is provided to draw the emulsion from the storage container. The emulsion storage container permits the supply of the mixture and the emulsion to the storage container at a rate independent of the rate at which the emulsion is drawn from the output circuit.