Abstract: A regulation and intensity controller for prolonging the life of an incandescent lamp controls the root mean square voltage across the lamp by converting AC voltage to a DC voltage and by applying the DC voltage to the lamp through a switch and an inductor in series connection with the lamp. The switch is opened and closed according to a duty cycle that will produce a constant average voltage across the lamp. The switch is closed at fixed intervals and is opened by a circuit that is responsive to the instantaneous current through the lamp and to a voltage signal produced by integrating an error signal that represents the difference between the lamp voltage and a reference voltage. In this manner, the average voltage across the lamp is regulated and ripple is kept within a level such that the average voltage is a close representation of root mean square voltage. Additionally, the cycle-by-cycle current through the lamp is closely regulated.

Abstract: A light fixture, particularly suitable for recreational vehicles, such as campers, trailers, boats and vans, consisting of a base having a reflector, lens and a bulb controlled by a slide switch. The switch is received within a "drop-in" mounting formed in the base and is retained in its mounting by a manually operated switch actuating slide. The retention structure slidably mounting the slide on the base in cooperation with slide structure superimposed over the switch retains the switch in position minimizing assembly procedures.

Abstract: A system for producing alternating electromagnetic fields for use in theft detection and surveillance systems, including an arrangement of field-generating inductance coils for disposition on opposite sides of a passage to be monitored by the electromagnetic field produced by such coils. In a preferred such arrangement, upper and lower coils are used on each side of the passage and such coils are mutually distinct from one another and separately energizeable so as to generate separate components of a resulting composite electromagnetic field. The upper and lower coils in each such set are preferably disposed in coplanar alignment with one another but have at least portions of one coil overlapping portions of the other, so as to enhance uniformity in the resulting electromagnetic field. The array of separately-energizeable coils provides for resultant flux vector variation in the magnetic field along three mutually orthogonal axes as a function of coil drive excitation phase variation.

Abstract: A voltage-agile, controlled output, regenerative-feedback power supply control circuit in which a power source is switched by a pair of controlled switch elements so as to supply a selective amount of output power to a load while also selectively completing a regenerative power feedback path, the switch elements preferably constituting FET switches of which a first is connected between the power source input and the circuit power output point and the second is connected between the circuit power output point and the circuit ground conductor. The gate terminals of the first and second FET switches are connected to receive generally opposite types of control signal representations of the level of circuit output power under load in relation to no-load output power.

Abstract: The specification discloses a digital/analog signal analyzer for an electromagnetic surveillance system. Included is a notch filter having a switched capacitor filter controlled by a phase lock loop for nulling a time-varying driving frequency from the received signal. The analyzer further includes structure for digitizing the received signal and for implementing a recursive filter to enhance digital feature extraction. The recursive filter in turn includes structure for delaying a read address for subsequent use as a write address to facilitate the rapid updating of data in memory. Also included is a digital-to-analog converter assembly having a pair of piggy-backed digital-to-analog converters to produce an analog signal dependent upon both a mantissa and an exponent of a digital number in scientific notation.

Abstract: Methods and apparatus for producing alternating electromagnetic fields for use in theft detection and surveillance systems include individual series-type electrical drive circuits for separately energizing each of the field-generating coil windings with maximum efficiency and control, and transformer-type coupling between the different field-generating coil drive circuits to effect balanced and equalized current flow in the different coil windings and thereby enhance both drive efficiency and field uniformity. Additionally, a current-sense winding provides for monitoring of field coil current flow, and for feedback control of the magnitude and/or frequency of the coil excitation drive. In a preferred embodiment, the fields are generated by at least two coils on each opposite side of the field, and the coils are separately energized through separate but commonly-coupled drive circuits.

Abstract: Improvements in theft-detection or surveillance systems of the type in which an alternating electromagnetic field is established across a doorway or other portal and is monitored to detect the presence within the field of a marker or tag member comprising a small strip of permalloy or like material of high permeability hidden or otherwise carried on merchandise or other articles and objects to thereby "mark" such merchandise or objects, i.e., to make them readily detectable even though hidden from view. More particularly regarded, the improvements in accordance herewith reside in signal-processing electronic circuitry which increases detection sensitivity and accuracy while at the same time reducing erroneous detection results.

Abstract: In an electromagnetic passage surveillance system, first and second receiver means are employed in mutually-spaced locations across a guarded portal to detect perturbations in an electromagnetic field extending across the portal, resulting from presence within the field of a high-permeability, low-coercivity marker. From the outputs of such receivers a sum signal and a difference signal are produced, and the high-order harmonics of the sum signal are emphasized to produce a first analysis signal while the low-order harmonics of the difference signal are emphasized to produce a second analysis signal. The ratio of the first analysis signal to the second, and thus the ratio of high-order to low-order harmonics, is used in logic and processing circuitry to dynamically vary the detection threshold by which the presence of a marker is determined.

Abstract: A power converter for recreational vehicles comprises a two-part housing construction having the ends of the electrical components of the converter telescopically received in aligned sockets formed in each of the mating housing members, whereby the electrical components are captured therebetween and securely mounted in the housing without separate or special fasteners.

Abstract: The invention pertains to a lampholder and switch module which may be readily installed in a lamp fixture, and is particularly suitable for automotive and recreational vehicle use. A housing includes a lamp socket having electrical contacts located therein, and a switch slidably mounted upon the housing employs cam structure for translating a contact between lamp base engaging and disengaging positions to selectively complete and break the circuit to the lamp. The module is characterized by its economics of fabrication, assembly, and installation.

Abstract: A direct current power supply system for recreational vehicles having an auxiliary chargeable battery wherein a transformer powered converter is utilized to rectify alternating current into direct current, and where the circuitry includes a battery fast charging circuit and control utilizing sensing means for automatically terminating battery fast charging upon predetermined conditions being attained. Fast charging of the battery is accomplished through a converter transformer of economical construction having a variable voltage output controlled in dependence by the fast charging operation.

Abstract: A vent cover for gas pressure regulators exposed to adverse weather conditions wherein the vent cover is mounted upon the vented neck of a gas regulator and is rotatably adjustable relative to the neck such that a vent opening defined in the cover may always be oriented downwardly regardless of the horizontal orientation of the regulator neck during installation. The downward orientation of the vent cover opening removes the possiblity of the regulator venting being rendered inoperable due to adverse weather conditions, such as icing.