No description available.

No description available.

Incandescent lamps are now being gradually replaced by Compact Fluorescent Lamps (CFLs) as CFLs consume less power to produce the same light output and its lifetime is much longer than that of an incandescent lamp. However, current CFLs have the following drawbacks: (1) the line current drawn from the CFL produce a large amount of unwanted harmonics that results in very poor input power factor; (2) the dimming performance of a CFL with conventional incandescent lamp dimmers is very poor. The performance of the CFL depends on the design of the electronic ballast circuit that is located at the base of each CFL. For a CFL electronic ballast to be practical, its size and cost is of utmost importance. Thus, the main challenge in the design of practical dimmable CFL ballasts is to solve the aforementioned CFL performance issues while minimizing its size and cost. In the first part of this dissertation, two novel high power factor single-stage electronic ballast topologies are proposed to solve the poor power factor issue of the CFLs that are currently on the market. Both proposed circuits have the following advantages: (1) only one switch is required in the power circuit; (2) the switch has both lower current and voltage stress than other conventional circuits; (3) the built-in power factor correction (PFC) circuit allows incandescent phase-cut dimmer to be used for dimming the CFL; (4) the circuit design is simple and it requires less system space compared to other conventional high PF electronic ballast topologies. The second part of this dissertation proposes a new control circuit that enables the lamp to maintain high power factor throughout the majority of the dimming range. In the proposed control scheme, the dimmer phase-cut angle is fed-forward to the control circuit. The controller then determines the proper duty cycle based on the phase-cut angle to facilitate the desired dimming operation. This novel control circuit was first implemented using analog circuitry. After assessing the performance of the analog version of the proposed controller, it was then digitally implemented through the Field Programmable Gate Array (FPGA) technique. The feasibility and performance of both the proposed electronic ballasts and control concept have been verified through theoretical analysis, simulation and experimental results on a 13W 4-pin D/E CFL from Osram Sylvania. / Thesis (Ph.D, Electrical & Computer Engineering) -- Queen's University, 2010-04-30 12:51:59.682

<p> In the field of Reliability, a new concept is introduced. The Combined Dependability theory is put forth in this thesis. </p> <p> Attempts are made to prove this theory experimentally by use of accelerated failure tests of GE-47 miniature lamps. The lamps are tested individually and ten in series. The individual lamp test results are then used for the prediction of the reliability of the ten lamps in series.</p> <p> The ten lamps in series simulate a machine with ten components. A failure of one of the components will produce a failure of the machine. The reliability of the machine can be found if the reliability of each part is known. The single part when tested individually must be subjected to the same stresses and conditions that it would encounter when operating in the machine. If this is not accomplished, the machine's calculation of reliability is invalid.</p> / Thesis / Master of Engineering (MEngr)

No description available.

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 111-118). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 111-118). Also available on the Internet.

The objective of this project is to design a facility that will characterize the electrical and optical properties of both tubular and the more recent compact fluorescent tubes. The first stage of this project, which is the subject of this dissertation, was to design, build, test, and model a cylindrical light integrating chamber. An integrating chamber capable of measuring 2-metre long fluorescent tubes was built at the University of KwaZulu-Natal, South Africa. To approximate an infinitely long tube, precisely mounted planar mirrors were placed at opposite ends of the cylinder. The reflectance of diffusive reflective paint and mirrors enter into calculations and were investigated experimentally using a Jarrel-Ash optical spectrometer. The light flux was finally measured for various chamber lengths and compared with a mathematical model. Total light power output from the lamp was calculated and compared with the electrical power input, and the lamp efficiency deduced. Accurate calculations required that the light field surrounding a cylindrical diffuse source be modeled mathematically. The reflection coefficients of the mirrors were not unity and the equations had to be modified to include this effect. The mathematical model was solved using a combination of analytical and numerical techniques. The model results were compared with measurements. The final result includes a mathematical description of the integrating chamber, and a flux-density plot of the space surrounding the fluorescent tube. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2008.

Thesis (doctoral)--Universität, Köln, 2004. / Includes bibliographical references (p. 147-162).

Thesis--Auburn University, 2009. / Abstract. Vita. Includes bibliographic references (p.104-110).