Abstract:
A method is provided for reducing the power rating of a current limiting resistor (R) in a branch circuit having at least one protected element and the current limiting resistor connected between first and second nodes. The method includes the steps of: determining a maximum fault current in the branch circuit; determining a total current limiting resistance to limit the current in the branch circuit having the short-circuited elements to the maximum fault current; inserting a fuse having an intrinsic resistance in the branch circuit; and dividing the determined total current limiting resistance between the resistor (R) and the intrinsic resistance of the fuse.
Abstract:
A handheld fluorescent task lamp comprising a housing assembly having a housing and a tubular lens body enclosing compact fluorescent bulbs, an elongated spine configured for slidingly supporting the lens body, and a resilient bulkhead for cushioning the compact fluorescent bulbs in the lens body; an electronic ballast circuit within the housing comprising a power supply, a self-starting electronic driver circuit operable to start and run at least first and second CFL bulbs; a bulb accommodation circuit that enables operation of the electronic ballast circuit with either starter type or non-starter type and regardless whether one or both CFL bulbs are connected to the driver circuit; and an illumination assembly, wherein the CFL bulbs are oriented with respect to each other such that an enhanced forward emission field is provided.
Abstract:
A single drive circuit is configured to drive disparate current loads of first and second combinations of compact light emitting devices with respective regulated constant currents. Standard push ON, push OFF latching switches provide independent control of the two lighting loads wherein each switch operates in three states including momentary ON, continuous ON, and OFF. The circuit is readily adapted to providing continuous or pulsed drive to the lighting arrays. Circuits for dimming control, strobe control, and a low battery indicator are also described.
Abstract:
A method of using a single pole, single throw switch having normally open contacts in a conductive path in a non-intuitive manner in an electric circuit to sequentially provide three operable states including latched engagement (path closed, circuit OFF), momentary disengagement (path opened, circuit ON momentarily), and latched disengagement (path open, circuit ON until switch actuated again).
Abstract:
An electronic ballast circuit for a handheld fluorescent task lamp, comprising a self-starting electronic driver circuit operated by a power supply and operable to start and run at least first and second compact fluorescent bulbs from a single output; first and second receptacles for connecting the first and second bulbs to the single output; and a bulb accommodation circuit in the electronic driver circuit that enables operation of the electronic ballast circuit with either starter or non-starter type fluorescent bulbs and with either one or both bulbs.
Abstract:
A handheld fluorescent task lamp comprising a housing assembly having a housing and a tubular lens body enclosing compact fluorescent bulbs, an elongated spine configured for slidingly supporting the lens body, and a resilient bulkhead for cushioning the compact fluorescent bulbs in the lens body; an electronic ballast circuit within the housing comprising a power supply, a self-starting electronic driver circuit operable to start and run at least first and second CFL bulbs; a bulb accommodation circuit that enables operation of the electronic ballast circuit with either starter type or non-starter type and regardless whether one or both CFL bulbs are connected to the driver circuit; and an illumination assembly, wherein the CFL bulbs are oriented with respect to each other such that an enhanced forward emission field is provided.
Abstract:
An intrinsically safe energy limited circuit for space-restricted applications includes a fuse and resistor in series with a protected circuit or component wherein the fuse dissipates most of the power when the protected circuit or component is short circuited.
Abstract:
A fluorescent task lamp includes a housing assembled from first and second shells for supporting a lens body, first and second CFL bulb receptacles and first and second CFL bulbs; and a strain relief for an AC power cord having an integral hub portion with first and second pivot pins that pivot within first and second opposing pivot bushings formed respectively in each first and second shell in opposite sides of an aperture or cavity for receiving the hub portion therein. The pivoting strain relief permits orienting the power cord so that the lamp may be stood upright upon its base or hung from its hook.