Abstract: The invention provides visual displays, and methods of operating such visual displays, in which use is made of a plurality of light emitting diode elements which are arranged to emit a respective colour when suitably energised. Diode elements having different colours are juxtaposed so that when one or some of the juxtaposed elements are energised they show a first colour, and when others of the juxtaposed elements are simultaneously energised, the elements collectively generate a further colour or colours which is or are a derivative of their respective colours. Examples are described of use of the visual displays for such purposes as the provision of advertising materials, decorative materials, and variable background shapes, colours and textures, such as for display and furnishings.

Abstract: An electronic instrument has a display with a group of light emitting diode elements, the elements of a first portion of the group being of a first color when energized, and the elements of a second portion being of a second color when energized. The elements of the first portion are juxtaposed to the elements of the second portion, so that when both elements are energized at the same time, they collectively display a third color which is a derivative of their respective colors.

Abstract: A meter measures a voltage across a quasi-diode, the voltage caused by a current flowing through a resistance which changes substantially exponentially with changes in a medium being sensed. The meter comprises a logarithmic current measuring circuit coupled to the resistance to provide a measurement output that is a logarithmic function of the current flowing through the sensing resistance. A switchable current source is controlled by a switching circuit to repetitively output first and second current values. A reference logarithmic circuit is connected to the switchable current source and is physically coupled to the logarithmic measuring circuit so as to be maintained at a substantially equal temperature value. The logarithmic reference circuit manifests a first voltage in response to the first current value and a second voltage in response to the second current value, both voltage values dependent upon the temperature of the logarithmic reference circuit.

Abstract: A processor is described for monitoring a sensor whose output signal follows a nonlinear curve in response to a linear change in a monitored phenomenon. The processor converts the sensor signal to a linear output proportional or equal to the phenomenon being monitored. The processor includes a memory for storing a table which includes a starting data point value S on the curve, a starting slope value S' to another data point on the curve, a starting curvature value S" for a succession of the data points on the curve and a plurality of rate of change of curvature values S'" for the curve. The values of S'" for a first region of the curve are calculated based on an initial output signal interval between data point values. The values of S'" for each succeeding region of the curve are based on increasing, by a preselected factor, the signal interval between data point values. The processor includes a calculation device for computing repeated aditons of the S', S", S'" values.