Global ETD Search
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 13 of 13 for “"variable capacitor"”.
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Surface micromachined MEMS variable capacitor with two-cavity for energy harvesting
In this research, a novel MEMS variable capacitor with two capacitive cavities for energy harvesting was developed that use the wasted energy associated with undesirable mechanical vibrations to power microelectronic sensors and actuators widely found in structures and systems surrounding us. The …
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A variable capacitor made from single crystal silicon fracture surface pairs
… optimized to apply pure tension. Prototype MEMS variable capacitors employing fracture surfaces as separable parallel plates have been developed. The advantage of fracture surfaces over etched surfaces is their exceptional flatness or complementarity, which allow them to very closely approach …
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Electrostatic vibration-to-electric energy conversion
… fundamental means of en- ergy conversion is a variable capacitor that is excited through a generating energy conversion cycle with every vibration cycle of the converter. This thesis presents a road map on how to design MEMS electrostatic vibration-to- electric energy converters. A proposed …
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Vibration-to-electric energy conversion using a mechanically-varied capacitor
… energy harvesting has focused on the use of variable capacitors, magnets, or piezoelectric materials as the basis of energy transduction. How- ever, few of these studies have explored the detailed circuits required to make the energy harvesting work. In contrast, this thesis develops and …
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Design of DC-DC converters using Tunable Piezoelectric Transformers
… circuit performance. Based on this analysis, a variable capacitor connected across the control terminal is proposed to regulate the output voltage for line and load variations is suggested. The concept of ‘tunability’ in a TPT is introduced and mathematical conditions are derived to achieve the …
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Optimization studies of thermal bimorph cantilevers, electrostatic torsion actuators and variable capacitors
… electrostatic torsion actuators, and variable capacitors. Calculation, simulation, and experimental data are used to confirm the device behavior and demonstrate the application of the design approaches. For thermal bimorph cantilevers, an analytical model is presented which allows …
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Design, Fabrication, and Characterization of an Array of Graphene Based Variable Capacitors
… create an array of freestanding graphene-based variable capacitors on 100 mm silicon wafer substrates. Our intent is to develop a device that can be highly duplicated and potentially incorporated into an integrated circuit to power low power electronics. </p> <p>This work is based on a two-mask …
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A low power controller for a MEMS based energy converter
… acting as the energy transducer in the form of a variable capacitor, with conversion controlled by employing low power digital control techniques. This thesis explores the design of such an energy converter. The theory behind the conversion process will be discussed, including the presentation of …
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Wide-Dynamic-Range Continuous-Time Delta-Sigma A/D Converter for Low-Power Energy Scavenging Applications
… the input-current is integrated onto a capacitor, either with a variable time, or a variable capacitor value, followed by a sample-and-hold and a voltage A/D converter. The penalty for achieving wide-dynamic-range with the above approach is power and circuit complexity. </p><p>We propose …
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Load-Independent Class-E Power Conversion
… over 20:1 output power range. Design of variable Capacitor by connecting two voltage-sensitive capacitors in series and controlling the bias voltage of them - The equivalent varying capacitance in the Class-E dc-dc converter can be compensated in the whole load range only with variable …
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Electrostatic micro actuators for mirror and other applications
… domain. The first method utilizes a series capacitor to modulate the effective actuation voltage across the variable capacitor micro mirror. The second method utilizes negative feedback due to the coulombic repulsive interaction between charge layers inserted between the micro mirror …
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Filter Design for Interference Cancellation for Wide and Narrow Band RF Systems
… Frequency tunability is accomplished by using a variable capacitor (varactor) and bandwidth tuning is carried out by employing a negative transconductance cell to compensate for the loss of the elements. Additional circuitry is added to the band pass filter to enhance the selectivity of the …
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Performance Optimisation of Dielectric Elastomer Generators
… basically a highly deformable parallel-plate capacitor, made up of a soft DE membrane coated with two compliant electrodes on its opposite surfaces. This device is able to convert mechanical work, emanating from its interaction with the environment, into electrical energy. The capacitance …