Topic
Rise time
About: Rise time is a research topic. Over the lifetime, 4748 publications have been published within this topic receiving 47512 citations.
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TL;DR: In this article, a signal processing algorithm, based on energy conservation requirements and Fourier analysis, for reconstruction of the wave form of the pressure wave generated under water by electrical explosion of wires is proposed.
Abstract: Investigation of underwater electrical wire explosions occurring in the time scale of few microseconds requires a measurement of pressure waves with nanosecond rise time and microsecond fall time. Various types of pressure gauges are used for this purpose, however, none of them seems to be suitable for the task since the frequency range of the pressure waves lies between 107 and 109 Hz, whereas all types of mechanical gauges have a bandwidth below 107 Hz. Therefore, a mathematical processing of measurements is required for reconstruction of the actual pressure wave forms. In this article, a signal processing algorithm, based on energy conservation requirements and Fourier analysis, for reconstruction of the wave form of the pressure wave generated under water by electrical explosion of wires is proposed. The gauge used in the experiments is a PCB 119A12 type pressure gauge with a bandwidth below 1 MHz produced by Piezo-Electronics, Inc. Pressure waves were produced by underwater electrical explosion of a thin wire made of Cu by a current pulse with an amplitude of 30–60 kA having a rise time of a 3 μs. It is shown that the error of the gauge in the measurement of the peak pressure is more than 100%, which leads to an error in the estimation of the energy of almost 300%.
41 citations
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28 Jan 1997TL;DR: In this article, a charge pump circuit with fast rise time and reduced physical area is described, which includes a plurality of stages having an non-uniform series of bootstrap capacitors.
Abstract: A charge pump circuit having a fast rise time and reduced physical area is disclosed. The charge pump includes a plurality of stages having an non-uniform series of bootstrap capacitors. By using non-uniform capacitors at the various stages, charging rise time is enhanced while at the same time reducing the overall physical size of the charge pump.
41 citations
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12 Dec 1996
TL;DR: In this article, a high power, high energy inductive ignition system with a parallel array of multiple ignition coils Ti (2a, 2b) and associated 600 volt unclamped IGBT power switches Si (8a, 8b), for use with an automotive 12 volt storage battery was presented.
Abstract: A high power, high energy inductive ignition system with a parallel array of multiple ignition coils Ti (2a, 2b) and associated 600 volt unclamped IGBT power switches Si (8a, 8b), for use with an automotive 12 volt storage battery (1), the system having an internal voltage source (12) to generate a voltage Vc approximately three times the peak primary coil current with coils Ti of low primary inductance of about 0,5 millihenry and of open E-type core structure for spark energy in the range of 120 to 250 mj, the system using a lossless snubber and variable control inductor (6) to provide very high circuit and component efficiency and high coil energy density, in mj/gm, three times that of conventional inductive ignition systems, and high output voltage of 40 kilovolts with fast rise time of 10 microseconds.
41 citations
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TL;DR: In this paper, a model for the rise times of elastic waves in polycrystalline metals is developed, which incorporates the following parameters: anisotropy of wave velocity, scattering by grain boundaries, mode conversion and deflection due to anisotropic of adjacent grains, dislocation effects, and intrinsic wave rise time.
41 citations
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TL;DR: An intelligent Mamdani type Fuzzy Logic-Proportional-Integral-Derivative (FLC-PID) controller has been additionally designed and its response simulated to demonstrate improved tracking capability, and hence, better control performance of FLC-PIDs for transient changes in product concentration.
40 citations