Abstract: In the type of ion mobility spectrometer having a unidirectional drift and source flow (30) which is exhausted (22) downstream of an ionisation source (10), improved sensitivity is obtained by entraining the effluent (18) from a gas chromatograph within a faster moving further gas flow (32), both being introduced in a direction counter to that of the said unidirectional flow.

Abstract: An improved vehicle transmission oil sump filling apparatus and method of using same, wherein the apparatus includes an integrally formed extension on the distal end of an otherwise conventional filler tube extending a predetermined distance into a transmission sump, and a sealed adapter assembly adaptable to being mounted in the entrance of the fill tube. The sealed adapter assembly includes a single short oil supply tube together with a pressurized air supply and sensing tube integrally formed therein. An air pump is operative for continually blowing air through the sensing tube while the transmission sump is being filled from a source of oil by a reversible oil pump. Once overfill of the sump is sensed, the overfill is drawn out under suction by the oil pump until reaching the point where air once again flows through the filler tube, indicating the appropriate sump oil level.

Abstract: A power supply for a laser diode comprising optical detector means coupled for monitoring the intensity of light emitted by the diode, the optical detector means being coupled, via capacitive means, for integrating the signal from the detector means, to the gate of a field effect transistor, the field effect transistor being coupled to the control electrode of a transistor means to control the main current path thereof, the transistor means being arranged to regulate the power supply to the laser diode, whereby the power output of the laser diode is stabilised. The power supply is incorporated with the diode in a module for connection to a printed circuit board for coupling to an optical fibre in a local area network.