Abstract: A universal dimmer which can be used for both fluorescent lamps having a ballast and for incandescent lamps connected to either an alternating or direct current power supply. The dimmer can be installed in place of a standard wall-mounted light switch and connected to the existing wiring. The dimmer circuitry has a fullwave diode rectifier bridge connected in series with the lamp for converting the alternating current power into direct current. A variable current limiting circuit is connected in series with the DC output of the rectifier bridge and is powered by direct current to control the amount of current supplied through the lamp and ballast. The current limiting circuit includes a power transistor which acts as a variable resistor and controls the lamp current and an operational amplifier coupled with a voltage divider network that establishes a selectively variable reference voltage which controls the amount of current through the lamp.

Abstract: A loop, formed in a single suspended strand of a photo-elastic material, serves as an inertia mass that is rotatable about the axis of the suspended strand. The angular displacement of the loop, due to an accelerating force, is measured as a function of the change in polarization angle of a radiant beam passing through the strand.

Abstract: An optical sound source signature transducer system for use in marine seismic exploration in which coherent radiation from a laser is coupled to unequal length optical paths exposed to modulation by the acoustic energy wave generated by the sound source. The reflected beams from the paths are crosscoupled to generate interference fringes in two output beams out of phase with each other. The fringes in one output beam are counted in an up/down counter to determine the magnitude of the pressure as a function of time. The direction of the pressure change is determined by examination of the phase relationship between the fringes in the output beams. Peaks and valleys in the pressure are detected as phase reversals between the fringes in the output beams be detecting the beginning and end of a fringe in one beam without detecting the beginning or end of a fringe in the other beam therebetween.

Abstract: A device for determining the stuck point of a drill pipe in a borehole consisting of two relatively movable sections, anchoring means for each section, a sensing means for detecting relative movement of the two sections and producing an inductance representative of the movement. The inductance is transformed into a frequency modulated signal which is transmitted to the surface and converted from a non-linear direct current voltage representation of relative movement to a linear direct current voltage.