A repeater for a transmission system which can pass signals in either of two directions. Each direction has a signal detection circuit associated with it. Upon detection of the beginning of a signal, the signal detection circuit enables an associated driver to pass the signal in the appropriate direction and at the same time disables the other signal detection circuit so that a signal will pass in only one direction at a time. An end flag detecting circuit monitors for certain characteristics as...

A battery charger for charging an electric battery pack has a supply rectifier connectable to the battery pack via a thyristor. A thermistor is mounted on a mechanical structure and brought into thermal contact with a cell of the battery pack to measure the temperature thereof. Comparators control the firing of the thyristor in dependence on the state of the thermal conductive relationship between the thermistor and the cell and also upon dependence of a correct electrical connection between the...

The specification discloses a ski boat having a swim platform across which a conventional water ski can be laid so that a skier can easily put the ski on while standing on the platform. More particularly the boat includes a pair of sidewalls and a swim platform integral with and extending between the sidewalls. The swim platform extends rearwardly beyond the sidewalls to provide a portion across which the ski can lie.

Cloning vectors are described which include the streptomycin resistance (Sm.sup.r) determinant derived from Tn904. A single site for the restriction endonuclease, AvaI, is present within the Tn904 determinant for Sm.sup.r. A method is described for preparing the Tn904 containing cloning vectors through transposition of Tn904 to a parent cloning vector and then cloning of the Sm.sup.r gene into another vector segment. The cloning vector is important for inserting deoxyribonucleic acid segments, w...

Oxidative conversion of olefins and/or diolefins including the dehydrogenation of organic compounds is carried out with an iron-phosphorus-oxygen catalyst wherein the amount of phosphorus is greater than the stoichiometric amount required to react with all of the iron in the catalyst and form monophosphate ions (PO.sub.4.sup..sup.-3). The activity of the phosphorus-containing catalyst can be maintained by continuous or intermittent addition of phosphorus containing compounds.

A rectifier circuit which uses transistors, is unaffected by changes in ambient temperature and frequency, and shows a linear relation between input AC and output DC. In the invention, the diode or diodes of a rectifier circuit are replaced by the emitter-collector path of a transistor (Q) and the base electrode of the transistor is connected to one of the output terminals 3 by means of a resistor R1 having a high resistance compared to the base input resistance of the transistor.

U.S. Pat. No. 3,533,155, whereof this is a division, concerns a method of bonding which employs a compliant or deformable medium to hold workpiece devices during bonding, the medium transmitting bonding energy to the workpieces and deforming about the workpieces. The invention of this division relates to the compliant medium and to an assembly, useful in compliant bonding of the type described in U.S. Pat. No. 3,533,155. The assembly is provided by the compliant medium plus the devices for which...

A switching circuit for a flash discharge tube includes a first thyristor in series with the tube across a DC voltage source. The thyristor is rapidly extinguished by an auxiliary circuit that includes, in series, a first capacitor, a second thyristor, and the parallel connection of a second capacitor and a resistor. A charge circuit for the first capacitor is connected partly in parallel with the tube and is exclusive of the first thyristor. A preferred embodiment also includes a diode in shunt...

A broiler for meats and the like has a bottom heat supply compartment and an oven compartment thereabove. The heating compartment has a top plate totally closing off the compartment from the oven thereabove. The oven has a rotisserie driven by a motor, and there are easily-removable meat carrying shelf-like members on the rotisserie. There is an access door in the oven and this operates a switch in a power supply circuit to an exhaust fan that is operated when the access door is open. Towards th...

A collimator is disclosed which may be energized by a light source such as a laser and which includes means having a large field of view for expediting the finding of the light reflected from a reflecting surface to be oriented. The collimator includes means having a small field of view for making final adjustments in orienting the reflector, there being no moving parts in or between these two means. A built-in, sturdy reference device is provided which is independent of small errors in adjustme...