Abstract: A switch for an inductive load includes a first leg having a first field effect transistor connected between one terminal of the load to the high potential terminal of a power supply and a second leg having a second field effect transistor connected between the other terminal of the load and the low potential terminal of the power supply. A plurality of current paths located on opposite sides of the load terminals connected in parallel and extend from one of the load terminals to one of the power supply terminals. Each current path includes an inductor connected in series with a diode. A choke energy path is associated with each current path and includes a diode connected in series with a resistors. The inductors in the current paths operate to inhibit reverse recovery current through the diodes while the choke energy paths dissipate oscillation energy in the switch upon operation of the transistors to connect the inductive load across the terminals of the power supply.

Abstract: The dew points of condensible hydrocarbon and water in a gas stream are determined independently in a single run by observing changes in intensity of light scattered from a mirror surface which is cooled to below both of the dew points. A decrease in intensity denotes the hydrocarbon dew point while an increase in intensity denotes the water dew point. The apparatus is simple and operates automatically. The mirror surface has a first polished and highly reflective portion and a second, roughened, less reflective portion. The intensity of scattered light is preferably monitored separately for each mirror portion.