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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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Journal ArticleDOI
TL;DR: A newly developed bipolar high voltage adder is proposed for generating fast narrow pulses as discussed by the authors, which enables the use of typical half-bridge semiconductor structures on the basis of conventional unipolar all-solid state pulse adder Magnetic ring transformers were employed for isolating the charge loop from the high-voltage pulse discharge loop, which simplified the isolation arrangement.
Abstract: A newly developed bipolar high voltage adder is proposed for generating fast narrow pulses The new circuit topology enables the use of typical half-bridge semiconductor structures on the basis of conventional unipolar all-solid-state pulse adder Magnetic ring transformers were employed for isolating the charge loop from the high-voltage pulse discharge loop, which simplified the isolation arrangement Certain measures were implemented to resolve the EMI caused by the pulse adder arrangement A laboratory prototype was assembled with 8 stages and each stage was made of 800 V MOSFETs The modulator operating at 21 kHz repetition rate gives 2 kV bipolar pulses, with 200 ns positive/negative pulse widths, 37 ns rise time, 50 ns fall time, and 40 ns relaxation time into a 50 Ω resistive load The adopted design is an all-solid-state approach with a simple control method, long maintenance-free lifetime, and high reliability

26 citations

Journal ArticleDOI
TL;DR: In this article, an electrically controllable magnetostrictive spring that has a dynamically tunable stiffness is presented, which enables in situ stiffness tuning or stiffness switching for vibration control applications.
Abstract: This paper presents the design and testing of an electrically controllable magnetostrictive spring that has a dynamically tunable stiffness (i.e., a magnetostrictive Varispring). The device enables in situ stiffness tuning or stiffness switching for vibration control applications. Using a nonlinear electromechanical transducer model and an analytical solution of linear, mechanically induced magnetic diffusion, Terfenol-D is shown to have a faster rise time to stepped voltage inputs and a significantly higher magnetic diffusion cut-off frequency relative to Galfenol. A Varispring is manufactured using a laminated Terfenol-D rod. Further rise time reductions are achieved by minimizing the rod's diameter and winding the electromagnet with larger wire. Dynamic tuning of the Varispring's stiffness is investigated by measuring the Terfenol-D rod's strain response to dynamic, compressive, axial forces in the presence of sinusoidal or square wave control currents. The Varispring's rise time is ms for 1 A current switches. Continuous modulus changes up to 21.9 GPa and 500 Hz and square wave modulus changes (dynamic effect) up to 12.3 GPa and 100 Hz are observed. Stiffness tunability and tuning bandwidth can be considerably increased by operating about a more optimal bias stress and improving the control of the electrical input.

25 citations

Journal ArticleDOI
TL;DR: R rise time of SCR which is related to recovery time was found to be related to cardiac acceleration and it is suggested on the basis of these preliminary results that the measurement of SCRs rise time should be undertaken in future studies.

25 citations

Journal ArticleDOI
TL;DR: In this paper, the use of ZnO-based metal-oxide-varistor materials in a transient protection device for communications circuits against the effects of nuclear electromagnetic pulses (NEMP) is discussed.
Abstract: The use of ZnO‐based metal‐oxide‐varistor materials in a transient protection device for communications circuits against the effects of nuclear electromagnetic pulses (NEMP) is discussed. The guidelines for such devices call for subnanosecond response time to NEMP and an insertion loss of less than 0.4 dB at 100 MHz. We have measured the response of varistor materials to ∼500‐ps rise time pulses of various amplitudes and durations. No varistor ’’turn on’’ time is evident in these data indicating that the initiation of the highly nonlinear conduction process takes place in less than 5×10−10 s. The insertion loss is calculated from the known high‐frequency electrical properties and found to agree quite closely with the experimentally determined value of 0.1 dB at 100 MHz for varistor chips of cross section 0.025×0.025 cm and thickness 0.01 cm. A packaging configuration for these chips is also described. We conclude that ZnO varistors have application in an NEMP protective device.

25 citations

Proceedings ArticleDOI
23 Jun 1992
TL;DR: In this paper, the effects of current filamentation on the location and number of current filaments, rise time, and delay to high gain switching, minimum trigger energy, and degradation of switch contacts are discussed.
Abstract: Characteristics of current filamentation are reported for high gain photoconductive semiconductor switches (PCSS). Infrared photoluminescence is used to monitor carrier recombination radiation during fast initiation of high gain switching in large (1.5 cm gap) lateral GaAs PCSS. Spatial modulation of the optical trigger, a 200--300 ps pulse width laser, is examined. Effects on the location and number of current filaments, rise time, and delay to high gain switching, minimum trigger energy, and degradation of switch contacts are presented. Implications of these measurements for the theoretical understanding and practical development of these switches are discussed. Efforts to increase current density and reduce switch size and optical trigger energy requirements are described. Results from contact development and device lifetime testing are presented and the impact of these results on practical device applications is discussed.

25 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202330
202264
2021111
2020146
2019157
2018147