Abstract: An apparatus is disclosed for monitoring usage of multiple electrical devices. The apparatus comprises multiple non-invasive current sensors for sensing current in respective conductors associated with the electrical devices. Such conductors may for example be the electrical power supply leads to the devices. The apparatus further includes multiple analogue to digital conversion functions for digitizing the output from the respective current sensors. A microprocessor is arranged to receive the digitized current sensor and is programmed to create usage data relating to the respective electrical devices. Such usage data may include cumulative elapsed running time. The microprocessor has an associated memory in which the usage data is stored in association with corresponding data identifying the electrical devices. The system further includes an interface through which the usage and identifier data are extractable, to provide usage information for the respective electrical devices.

Abstract: A method and control circuit are disclosed for controlling light emitting diodes (“LEDs”). Based upon the LED's current versus intensity characteristic and temperature versus intensity characteristic, the rate of change of LED output intensity with respect to current is calculated. Adjusting LED current to provide zero rate of change ensures that LED output is maximised.

Abstract: The present invention discloses an electronic tag comprising electronic circuitry incorporating a microprocessor (44), a non-volatile memory associated with the microprocessor (44) such that the microprocessor (44) can write data to the non-volatile memory, a sensing transducer (54) connected to the microprocessor (44), and an interface (30) for interrogation of the non-volatile memory, the sensing transducer (54). being such as to output an electrical signal in response to an event of a pre-selected type, the microprocessor (44) being programmed to log signals from the sensing transducer (54) to the non-volatile memory to produce a record of the selected event and being arranged to be powered by the electrical output signal from the sensing transducer (54).