Abstract: An improved inverter or "fluorescent battery pack" useful particularly in an emergency lighting system with both magnetic and electronic ballasts of both "rapid start" and "instant start" configurations, the present inverter is rapidly installable in emergency lighting systems which include fluorescent lighting fixtures operable with either magnetic ballasts which are typically "non-isolated" or electronic ballasts which are typically "isolated". The inverter circuitry of the invention is simply installable in the present emergency lighting system due to an effective disconnection of the ballasts with concurrent connection between the inverter and lamping, only two effective connections to the lamp thus being necessary with a resulting avoidance of wiring redundancy.

Abstract: Circuitry for operating an array of light emitting diodes such as in an emergency exit sign in a non-emergency AC mode while concurrently charging and maintaining the charge of a low-voltage battery used to drive the array in an emergency mode, the circuitry also allows operation of the same LED array in the emergency mode from the low-voltage battery. The advantages of the invention are realized in part through provision within the circuitry of a boost converter wherein the LED array and the battery are connected across the output of the usual boost circuit output capacitor, thereby allowing connection of the array and the battery in series to simplify operation from line power and to allow the same current limited source to operate the array and simultaneously charge the battery through the same current path. The functions so provided can be embodied in a form which allows all circuitry components including the battery to be mounted on a single, compact substrate such as a printed circuit board.

Abstract: Battery charging circuits configured as a combination of current limited charging sources and a shunt regulating path to bypass current from a battery charging path through a low impedance path so that charge current can be regulated and terminated or controlled, the invention further includes combination of the circuits in emergency lighting systems utilizing conventional AC mains power in a non-emergency mode and DC battery power in an emergency mode, the battery being charged with regulation of charge current effected by said circuits when in the non-emergency mode. In the present circuits, current is by-passed from that portion of the circuit used for battery charging by provision of a low impedance alternate path through which current may also be supplied to non-emergency lamps, the alternate path supplanting prior art circuits which function by continuously turning a single path on and off for charge regulation.

Abstract: A retrofittable lamp using light emitting diodes as the illumination source, the lamp is fitted with any one of the common lamp bases and is intended as a retrofit for incandescent lamps having such bases in illuminated signs such as exit signs and the like. The invention contemplates the packaging of a number of light emitting diodes in a circuit usually having a current limiting device to allow LED operation at a desired current level. The light emitting diodes are placed within a standard glass or plastic bulb envelope in arrangements capable of providing even illumination from the lamp.

Abstract: An emergency lighting system operable on line voltage under normal conditions and on battery power upon failure of line voltage, the system comprises a battery, a battery charging circuit, a line monitor, a lamp/ballast interface and a switching transistor inverter circuit in addition to an electric discharge lamp, ballast and conventional associated circuitry as well as mechanical packaging and connections to line voltage. Advantages in installation and operation of the present emergency lighting system occurs through use of the switching transistor inverter circuit which starts and operates the discharge lamp from the battery on line voltage failure. The emergency lighting system of the invention is rapidly installable through wiring of an associated lighting fixture to the system using power input leads to conventional ballast, thereby substantially simplifying installation of the inverter circuit.

Abstract: A lead-type ballast apparatus for operating a HID high-pressure sodium lamp. The ballast apparatus includes an additional capacitor associated with the input portion thereof which provides a desirable power factor for the life of the lamp. Also disclosed is the addition of a supplemental winding to which the additional capacitor is connected that results in diminished operating losses for the ballast apparatus as the lamp ages.

Abstract: A shielding bladder for the venting arrangement of a linear actuator having a housing, a reciprocable member disposed therein for linear reciprocable movement therethrough, and a venting arrangement in the housing for communicative flow of ambient air into and out of the housing during operation. The bladder is a sleeve sealably affixed exteriorly to the housing enclosing the venting arrangement and defining a chamber between the sleeve and housing that contains a volume of air for contractionally expelling the air into the housing in response to increases in its volumetric capacity resulting upon outward reciprocation of the reciprocating member and expansionally receiving air from the housing in response to decreases in its volumetric capacity upon inward reciprocation of the reciprocating member.

Abstract: A lighting apparatus which provides for high-voltage pulses for starting a high-pressure sodium discharge lamp and thereafter provides operating ballasting. The apparatus uses two capacitors and associated blocking diodes and a charging resistor. One of the capacitors charges toward the peak of the line voltage in the negative half cycle, and thereafter, when the line voltage goes positive, the voltage on the one capacitor is added to the line voltage for charging the other capacitor. When the voltage on the other capacitor reaches a predetermined voltage exceeding the Zener voltage of a paralleling Zener diode which Zener voltage may be about twice the peak voltage of the line, the other capacitor discharges through a ballast inductor which is connected in autotransformer relationship therewith to provide a high voltage pulse of sufficient magnitude to start the lamp.

Abstract: A lighting apparatus which provides for high-voltage pulses for starting a high-pressure sodium discharge lamp and thereafter provides operating ballasting. The apparatus uses a single capacitor in series with a blocking diode and a charging resistor. When the voltage on the capacitor reaches a predetermined voltage exceeding the Zener voltage of a parallel Zener diode, the capacitor discharges through a ballast which is connected in autotransformer relationship therewith to provide the high-voltage pulse to start the lamp.