Abstract: An inhaler device which includes a wick which draws water from a reservoir and which is in contact with a heated plate. Air is directed over the heated wick surface by means of a fan thereby to produce a stream of heated humid air. A sensor monitors the temperature of the heated air stream and a control circuit which is responsive to the sensor maintains this temperature substantially constant at a predetermined value. The heated humid air stream is available for inhalation by a patient for the treatment of certain ailments.

Abstract: In an electronic amplifier having a floating output stage (42), a demand signal modulates a high frequency carrier (e.g. 20MHz) and the modulated carrier is applied to the floating output stage through a capacitance (10) of very low value (e.g. 1pf) and is then demodulated. The amplifier is preferably a bridge amplifier and each arm of the bridge may comprise a number of floating output stages, each supplied with the modulated carrier through a low-value capacitor (10). As described, the amplifier drives a crystal (40) for modulating electromagnetic radiation from a laser.