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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 17 of 17 for “"Ceramic capacitors"”.
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Breakdown in high voltage, high energy density multilayer ceramic capacitors
… voltage, high energy density, BaTiO₃ multilayer ceramic capacitors were studied. The flexural strength of the capacitors was 96 +/- 13 MPa. Failure was due to surface defects or pores close to the surfaces of the samples. The dielectric breakdown strength of the samples was 181 kV/cm. The causes …
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Intrinsic degradation mechanisms of barium titanate based multilayer ceramic capacitors
… intrinsic degradation behavior of X7R and Z5U capacitors. The major goals of this research were: 1) to determine current-voltage, activation energy and leakage current characteristics for such capacitors. 2) to investigate how these characteristics change with degradation; 3) to investigate …
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Electrical conduction transport mechanisms of barium titanate- based multilayer ceramic capacitors
… conduction properties of BaTiO3-based multilayer ceramic ( MLC ) capacitors in order to gain a better understanding of the conduction transport mechanisms inside the devices. The experiments involved mainly leakage current versus time measurements under both low temperature-low voltage stress and …
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Temperature Compensating Ceramic Capacitors in the System Baria-Rare-Earth-Oxide - Titania
Made available in DSpace on 2014-12-10T17:32:36Z (GMT). No. of bitstreams: 1 6812084.pdf: 1624899 bytes, checksum: c1d10b4a0e17b97b130947dafa6d553e (MD5) Previous issue date: 1968
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Impedance characteristics and grain boundary effects in titanate-based multilayer ceramic capacitors
… boundaries have on conduction in multilayer ceramic (MLC) capacitors. Electrical measurements were made so that current-voltage curves and impedance plots could be constructed. It was found that the current-voltage curves of new COG and X7R multilayer ceramic capacitors are both ohmic at low …
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Flex Cracking and Temperature-Humidity-Bias Effects on Reliability of Multilayer Ceramic Capacitors
Multilayer ceramic capacitors (MLCCs) are known to be susceptible to cracking when subjected to excessive printed circuit board (PCB) flexure, which is called "flex cracking". The bending of the printed circuit board causes stresses to be transmitted through the solder fillets to the surface mount …
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Effects of a combined supercritical extraction/thermal cycle on binder removal cycle time, yield, residual carbon, and defect formation in multilayer ceramic capacitors
… was used to remove binder from green multilayer ceramic capacitors. The dielectric was barium titanate and the binder consisted of poly(vinyl butyral) plasticized with phthalates. Supercritical extraction of approximately one-third of the binder leads to an increase in the porosity and gas …
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Stacked switched capacitor energy buffer architecture
Electrolytic capacitors are often used for energy buffering applications, including buffering between single-phase ac and dc. While these capacitors have high energy density compared to film and ceramic capacitors, their life is limited and their reliability is a major concern. This thesis presents …
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High-density multilevel power converters for use in renewable and transportation applications
… energy-dense electrolytic or low-loss film-based capacitors, designers now have an increasing array of high-energy-density ceramic capacitors available to them. In addition to the small signal characteristics of these devices which are typically provided by the manufacturer, designers need to …
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Design and Control of Charge-Pumped Reboost Converter for PV Applications
… The design avoids the use of electrolytic capacitors in favor of smaller ceramic capacitors and a few large film-capacitors. A simplified model is proposed which is still suitable for use in the design of high-bandwidth control loops. Testing is done with a PV source showing preliminary …
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Modeling of V2 Control with Composite Capacitors and Average Current Mode Control
… 2. modeling of V2 control with composite capacitors. This thesis tries to solve these two problems and starts with V2 control. For V2 control with single type of bulk capacitors, an accurate model has been proposed previously. In this thesis, an equivalent circuit model is proposed to get …
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Soft Switching Control and Loss Analysis for High Frequency Power Converters
… due to the need for bulky filter inductors and capacitors. Wide bandgap (WBG) power semiconductor devices are considered game-changing devices to overcome the limitation posed by traditional Si counterparts, enabling us with much higher switching speed and lower switching loss. However, when the …
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Power processing and active protection for photovoltaic energy extraction
… specification, and enable the use of film or ceramic capacitors to prolong the system lifetime to over a hundred years. The third part of this thesis explores the SC energy buffer design space and examines tradeoffs regarding circuit topology, switching configuration, and control complexity. …
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Modeling and Stability Analysis for Multiphase Constant On-Time Control With Phase Overlapping
… V² COT buck converters, even large ESR OSCON capacitors cannot ensure stability with phase overlapping. Hence, external ramp compensation is required to ensure stability when phase overlapping occurs. However, an external ramp can ensure stability only if the output voltage ripple has …
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Equivalent Circuit Model of High Frequency PWM and Resonant Converters
… which casues the instability problem when ceramic capacitors are employed, also needs to be taken into consideration in modeling. Chapter III proposed a unified equivalent circuit model of V2 control, the model is built based on non-ideal voltage source concept. The model represents …
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Compact and efficient power electronics with applications to solar PV, automotive, and aerospace systems
Improving the power density of a power converter has many benefits for systems integration. Aspects such as thermal management, weight, conformation to mounting locations, and the footprint of the converter all become critical factors as systems continue to scale down in size. The flying-capacitor …
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Synthesis-Structure-Property Relationships in Lead-Free Piezoelectric Materials
… agencies across the globe. In the functional ceramics community, currently there is no problem more important than to find a replacement for lead-based piezoelectrics used for actuators. The electromechanical properties required for actuators (high piezoelectric constant, high coupling factor, …