236 results on '"Farad"'
Search Results
152. Progress in Development of the Measurement Equipment for the Link Between DC QHR and Capacitance Standards in MIKES
- Author
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A. Satrapinski and Y.P. Semenov
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Engineering ,Wheatstone bridge ,business.industry ,Electrical engineering ,Capacitance ,law.invention ,Capacitor ,law ,Calibration ,Electronic engineering ,Farad ,Measurement uncertainty ,Resistor ,Coaxial ,business - Abstract
Results on development of the measurement setup for representation of the farad from DC QHR in MIKES are presented. Measurement chain and designed equipment used in the link between QHR and capacitance are described. Expected uncertainty is parts in 107. The important components of that chain, the standard combining 100 kOhm resistors and 1 nF capacitors and AC 10:1 self-calibrated coaxial resistance bridge, are described in this paper more...
- Published
- 2004
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153. Improved 1 kHz capacitance calibration uncertainty
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A.D. Koffman and A.-M. Jeffery
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Engineering ,Traceability ,business.industry ,Electrical engineering ,Capacitance ,law.invention ,Capacitor ,law ,Calibration ,Farad ,Measurement uncertainty ,NIST ,business ,Electrical impedance - Abstract
Uncertainties for 1 kHz capacitance calibrations have been decreased at the National Institute of Standards and Technology (NIST). The improvements are based on frequency-dependence characterization from 1592 Hz to 1 kHz. The relevant measurements and the traceability procedures from the calculable capacitor to the customer calibration are described. more...
- Published
- 2003
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154. An inductive voltage calibration system based on bootstrapping method
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Turgay Özkan, Enis Turhan, Gulay Gulmez, and Yakup Gulmez
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Engineering ,Bootstrapping ,business.industry ,Voltage divider ,Calibration ,Electronic engineering ,Farad ,Measurement uncertainty ,Ohm ,business ,Audio frequency ,Voltage - Abstract
The need of calibrated inductive voltage dividers (IVD) with the smallest possible uncertainties was appeared for determination, maintenance and dissemination of the ohm and the farad in audio frequencies. In this paper an IVD calibration system that is based on bootstrapping method is described and the preliminary results and improvement efforts are mentioned. The relative uncertainty of the system from the preliminary results is 2.10/sup -8/ for the inphase component, 5.10/sup -8/ for the quadrate component at 1 kHz. more...
- Published
- 2003
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155. A new method and test structure for easy determination of femto-farad on-chip capacitances in a MOS process
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B. Laquai, B. Hofflinger, and H. Richter
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Engineering ,FO4 ,business.industry ,Femto ,Electrical engineering ,Hardware_PERFORMANCEANDRELIABILITY ,Chip ,Capacitance ,CMOS ,Gate array ,Hardware_INTEGRATEDCIRCUITS ,Electronic engineering ,Farad ,Wafer ,business - Abstract
A new method and test structure for the easy measurement of on-chip capacitances are described. With relatively simple equipment an accuracy that allows measurements in the femto-farad range can be obtained. Test structures have been realized on a test chip in a 1.2- mu m CMOS process in a gate array environment. The accuracy of the method was demonstrated with a comparative measurement of a chip-external 10-pF capacitance with a conventional method. The measurements of on-chip capacitances showed good conformity to simulations. It was shown that the method is well suited for measurements with a digital verification tester and a wafer prober with minimum overhead. > more...
- Published
- 2003
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156. Electrical measurements
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M.L. Sanderson
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Computer science ,Power factor ,Capacitance ,law.invention ,symbols.namesake ,Electrical resistance and conductance ,law ,Thermocouple ,Farad ,Electrical measurements ,Ohm ,Ampere ,Physics ,Dynamometer ,Electromotive force ,Condensed matter physics ,business.industry ,Electrical engineering ,Volt ,Galvanometer ,Electromagnetic coil ,symbols ,Constant current ,Alternating current ,business ,Voltage - Abstract
Publisher Summary This chapter discusses the electrical measurements, such as units and standards of electrical measurement, and measurement of DC and AC current. The most commonly used instruments for providing an analog indication of direct or alternating current or voltage are the permanent magnet-moving coil, moving iron, and dynamometer instruments. Other indicating instruments include thermocouple and electrostatic instruments, the latter based on the attraction between two charged plates. Along with this, the permanent magnet-moving coil instrument is discussed. It is based on the principle of the D’Arsonval moving-coil galvanometer, the movement of which is also used in light spot galvanometers and pen and ultraviolet recorders. Analog indicating instruments provide a simple and relatively cheap method of indicating trends and changes in measured quantities. Power factor management is also explained as it is important in industrial power supply, since generating bodies penalize users operating on poor power factors, because this requires high current-generating capacity but low energy transfer. It is possible to employ the dynamometer principle to provide an indicating instrument for power factor. more...
- Published
- 2003
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157. Counting electrons one by one-overview of a joint European research project
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H.E. van den Brom, O. Kerkhof, S.V. Lotkhov, Sergey.A. Bogoslovsky, G.-D. Willenberg, H. Scherer, A.B. Zorin, S. Pedersen, C. Kristoffersson, A. Aassime, P. Delsing, M.A. Taslakov, Z. Ivanov, H. Nilsson, S. Giblin, P. Kleinschmidt, C. Hof, A.L. Eichenberger, F. Overney, B. Jeanneret, G. Genevis, N. Feltin, L. Devoille, F. Gay, and F.P.M. Piquemal more...
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Physics ,business.industry ,Electrical engineering ,Electron ,LC circuit ,Current source ,Capacitance ,law.invention ,Capacitor ,law ,Farad ,Electrical and Electronic Engineering ,Resistor ,Current (fluid) ,business ,Instrumentation - Abstract
The European COUNT project exploits two complementary single electron tunneling devices for use in electrical current metrology: a single electron pump as a current source and a single electron counter as a current meter. An electron pump has been developed with on-chip resistors in order to suppress cotunneling. The intended accuracy is 1 ppm for a current of a few picoamperes. Apart from being a quantum current standard, the electron pump could also be the basis of a capacitance standard. A coaxial tunable cryogenic capacitor of 1 picofarad has been developed for this purpose. A passive electron counter based on a single electron transistor embedded in a resonant tank circuit has been further investigated and developed in order to reach both high sensitivity and high counting speed. The intended accuracy is 10 ppm for a current of a few picoamperes. more...
- Published
- 2003
158. Final report: COOMET supplementary comparison of capacitance at 10 pF and 100 pF (COOMET.EM-S13)
- Author
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Sergii Shevkun and Oleh Velychko
- Subjects
General Engineering ,Farad ,Arithmetic ,Mutual recognition ,Reference standards ,Capacitance ,Mathematics - Abstract
An intercomparison of 10 pF and 100 pF capacitance standards has taken place within the framework of COOMET. The intercomparison, piloted by State Enterprise 'Ukrmetrteststandard'?UMTS (Ukraine), has involved tree laboratories, including one who is a member of another regional metrological organization?EURAMET (GUM, Poland). The results presented in this report appear to show that there are significant differences between some laboratories' representations of the farad. However, the agreement demonstrated by the intercomparison provides confidence in maintaining traceability for the farad either via a calculable capacitor or via the quantum Hall reference standard of the BIPM. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA). more...
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- 2015
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159. Quadrature bridge for the comparison of quantum Hall resistors with capacitors
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B. Schumacher and J. Melcher
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Engineering ,Condensed matter physics ,business.industry ,Electrical engineering ,Quantum Hall effect ,Omega ,Quadrature (astronomy) ,law.invention ,Capacitor ,Electrical resistivity and conductivity ,law ,Farad ,Resistor ,business ,Electronic circuit - Abstract
A quadrature bridge for the comparison of two quantized Hall resistances R/sub H/(2)=12906.4035 /spl Omega/ and two 10 nF capacitances is described The bridge was designed for a high-precision determination of the von Klitzing constant in SI units, based on a realisation of the farad via the Thompson-Lampard capacitor. > more...
- Published
- 2002
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160. High rate, solid-state electrochemical capacitors
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J.E. Oxley
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Materials science ,Analytical chemistry ,chemistry.chemical_element ,Electrolyte ,Electrochemistry ,Capacitance ,law.invention ,Capacitor ,chemistry.chemical_compound ,chemistry ,law ,Nafion ,Electrode ,Electronic engineering ,Farad ,Titanium - Abstract
The electrodes presently described are based upon RuO/sub 2/, prepared by thermal decomposition of RuCl/sub 3/-xH/sub 2/O onto titanium or tantalum foil substrates. A high area, thin, bipolar cell design is needed to derive full advantage from the high capacitance densities intrinsic to electrochemical capacitors. Capacitance loading (Farads/gram) can be maximized by the use of pseudocapacitive electrode materials such as RuO/sub 2/ or IrO/sub 2/, without appreciably sacrificing rate capability. The feasibility of constructing ultrathin bipolar devices utilizing Ti/RuO/sub 2/ electrodes, and the solid polymer electrolyte Nafion, cast from solution phase, was demonstrated. A significant finding was that the same capacitance value per unit area was achieved, independent of the electrolyte used, H/sub 2/SO/sub 4/ or Nafion. This indicates that the author was able to achieve the same penetration of the electrode with Nafion as with H/sub 2/SO/sub 4/. > more...
- Published
- 2002
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161. Determination of the volt with the improved PTB voltage balance
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V. Sienknecht and T. Funck
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Physics ,Kilogram ,business.industry ,Mean value ,Analytical chemistry ,Electrical engineering ,Conversion factor ,Volt ,Capacitance ,Standard deviation ,Farad ,Electrical and Electronic Engineering ,business ,Instrumentation ,Voltage - Abstract
Determinations of the conversion factor of the volt have been carried out after significant improvements to the measuring system. The mean value of 48 determinations was K/sub V/=1-0.02*10/sup -6/, with a standard deviation of the mean s/sub m/=0.064*10/sup -6/. The corresponding frequency-to-voltage quotient is K/sub J/=483597.91 GHz/V. The relative type B uncertainty of the experiment was estimated to be u=0.33*10/sup -6/. These data are preliminary, in as much as the recalibration of the standards used for the capacitance, the mass, and the displacement in terms of the SI units farad, kilogram, and meters had not yet been carried out. > more...
- Published
- 2002
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162. An implantable telemetry system powered by a capacitor having high capacitance
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Yoshiharu Yonezawa, E. Harada, Ishio Ninomiya, and Maki H
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Engineering ,business.industry ,Remote patient monitoring ,Electrical engineering ,High capacitance ,Integrated circuit ,law.invention ,Power (physics) ,Capacitor ,Transmission (telecommunications) ,Hardware_GENERAL ,law ,Telemetry ,Hardware_INTEGRATEDCIRCUITS ,Electronic engineering ,Farad ,ComputerSystemsOrganization_SPECIAL-PURPOSEANDAPPLICATION-BASEDSYSTEMS ,business - Abstract
An implantable telemetry system, using a capacitor having high capacitance instead of the rechargeable batteries, has been designed for chronic unanaesthetized animal studies. This system can simultaneously record the cardiac sympathetic nerve activity and ECG. The power of the system is inductively coupled and transmitted to a 2.5 farad capacitor. The system, which is constructed by ultralow power analog and digital standard integrated circuits, has a transmission range up to 5 m, depending on intervening tissue depth and FM receiver characteristics. With the capacitor charging time of 5 minutes, the system can be driven for 120 minutes. more...
- Published
- 2002
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163. Realization of the farad at BNM-LCIE
- Author
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G. Trapon, J.-C. Lacueille, O. Thevenot, and G. Geneves
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Interferometry ,End effect ,business.industry ,Mathematical analysis ,Electrical engineering ,Measurement uncertainty ,Farad ,Sigma ,business ,Capacitance ,Realization (systems) ,Lateral displacement ,Mathematics - Abstract
The BNM-LCIE Thompson Lampard Calculable Capacitance (TLCC) has been taken apart for improvements between 1994 and 1997. Influencing parameters were determined and/or corrected: parallelism of the electrodes, end effects, dimensions of a compensating spike and effect of its lateral displacement. With these improvements and by using a new interferometer, the realization of the farad is achieved with an uncertainty (not taking into account the frequency dependance of the TLCC) equal to 3 10/sup -8/ (1/spl sigma/). more...
- Published
- 2002
- Full Text
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164. Comparison of capacitance with AC quantized Hall resistance
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A. Hartland, S W Chua, and B.P. Kibble
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Engineering ,Electromagnetics ,business.industry ,Electrical engineering ,Macroscopic quantum phenomena ,Quantum Hall effect ,Capacitance ,law.invention ,law ,visual_art ,visual_art.visual_art_medium ,Optoelectronics ,Farad ,Ceramic ,Electrical and Electronic Engineering ,Resistor ,business ,Instrumentation ,Electrical conductor - Abstract
A quadrature bridge operating at a frequency of 1.233 kHz has been developed to compare 10 nF capacitances to the quantized Hall resistance on the i=2 plateau in order to realize the farad in terms of R/sub K/. Portable precision ceramic capacitance transfer standards of remarkable performance have been developed for this purpose. more...
- Published
- 2002
- Full Text
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165. Hybrid fuel cell for pulse power applications
- Author
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L.P. Jarvis, Terrill B. Atwater, and Peter J. Cygan
- Subjects
Engineering ,business.industry ,Continuous operation ,Electrical engineering ,Proton exchange membrane fuel cell ,Pulsed power ,law.invention ,Capacitor ,Direct energy conversion ,law ,Hybrid system ,Farad ,business ,Voltage - Abstract
A hybrid fuel cell demonstrated pulse power capability. It successfully ran a pulse power load simulation synonymous with electronics and communications equipment. The hybrid consisted of a 25 W proton exchange membrane fuel cell (PEMFC) stack in parallel with a 70 farad capacitor assembly. A cyclic regime of 18.0 W for 2 minutes followed by 2.5 W for 18 minutes was chosen as the basic test regime. The operating potential cut-off voltage for pass/failure was set to 3.0 V. At room temperature (23-25/spl deg/C), the PEMFC alone could not successfully power the baseline regime previously described. The PEMFC operating potential dropped below 3.0 V within 10 seconds. The hybrid continuously powered the cyclic regime for 25 hours. The hybrid's operating potential never reached the voltage cut-off, even during the high load of 18.0 W. The tests were aborted after 25 hours of operation with no signs of output degradation, suggesting that continuous operation is possible. more...
- Published
- 2002
- Full Text
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166. An on-chip, interconnect capacitance characterization method with sub-femto-farad resolution
- Author
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Hitoshi Aoki, Dennis Sylvester, Chenming Hu, S. Nakagawa, J.C. Chen, and S.-Y. Oh
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Engineering ,Interconnection ,business.industry ,Femto ,Hardware_PERFORMANCEANDRELIABILITY ,Integrated circuit ,Capacitance ,law.invention ,Capacitor ,law ,Hardware_INTEGRATEDCIRCUITS ,Electronic engineering ,Metre ,Farad ,Sensitivity (control systems) ,business - Abstract
In this paper, a sensitive and simple technique for parasitic interconnect capacitance measurement with 0.01 fF sensitivity is presented. This on-chip technique is based upon an efficient test structure design. No reference capacitor is needed. Only a DC current meter is required for its measurement. We have applied this technique to extract various interconnect geometry capacitances and compared the results to those from 3D simulations. more...
- Published
- 2002
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167. An integrated tactile-thermal robot sensor with capacitive tactile array
- Author
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F. Castelli
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Materials science ,business.industry ,Capacitive sensing ,Thermal resistance ,Acoustics ,Electrical engineering ,Linearity ,Hardware_PERFORMANCEANDRELIABILITY ,Industrial and Manufacturing Engineering ,Control and Systems Engineering ,Thermal ,Hardware_INTEGRATEDCIRCUITS ,Farad ,Electrical and Electronic Engineering ,business ,Temperature coefficient ,Image resolution ,Tactile sensor - Abstract
The paper discusses a tactile sensor system with high sampling resolution integrated with a thermal sensor. The integration is performed by using the column armature of the matrix of a capacitive tactile sensor as thermal resistor having positive temperature coefficient. A prototype of the sensor has been designed and constructed. From test results on this prototype when used as a tactile sensor, with spatial resolution of 2 mm, has been detected a sensitivity of about 20 N/mm/sup 2/ per picofarad or 0.05 pF per N/mm/sup 2/ with linearity of about 0.4%. As thermal sensor, with spatial resolution of 2 mm, the temperature coefficient has been in about the 0.4% with sensitivity of about 0.4 m/spl Omega///spl deg/C. more...
- Published
- 2002
- Full Text
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168. Electrical through-wafer interconnects with sub-picofarad parasitic capacitance [MEMS packaging]
- Author
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Butrus T. Khuri-Yakub, Ching-Hsiang Cheng, and A.S. Ergun
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Microelectromechanical systems ,Materials science ,business.industry ,Electrical engineering ,Hardware_PERFORMANCEANDRELIABILITY ,Capacitance ,Capacitive micromachined ultrasonic transducers ,Parasitic capacitance ,Etching (microfabrication) ,Hardware_INTEGRATEDCIRCUITS ,Farad ,Deep reactive-ion etching ,Optoelectronics ,Wafer ,business - Abstract
This paper presents a technology for high density and low parasitic capacitance electrical through-wafer interconnects to an array of capacitive micromachined ultrasonic transducers (CMUTs) on a silicon wafer. Vertical wafer feedthroughs (interconnects) connect an array of sensors or actuators from the front side (transducer side) to the backside (packaging side) of the wafer. A 20 to 1 high aspect ratio 400 /spl mu/m long and 20 /spl mu/m diameter interconnect is achieved by using deep reactive ion etching (DRIE). Reduction of the parasitic capacitance of the polysilicon pads to the substrate can be achieved by using reversed-biased pn-junction diodes operating in the depletion region. A parasitic capacitance of 0.3 pF has been achieved by this means. This three-dimensional architecture allows for elegant packaging through simple flip-chip bonding of the chip's back side to a printed circuit board (PCB) or a signal processing wafer. more...
- Published
- 2002
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169. Report on the CCEM comparison of 10 pF capacitance standards
- Author
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A.-M. Jeffery
- Subjects
Capacitor ,Engineering ,business.industry ,law ,Electrical engineering ,Electronic engineering ,Farad ,business ,Capacitance ,law.invention ,Metrology - Abstract
This paper describes the recent Comite Consultatif d'Electricite et Magnetisme (CCEM) comparison of 10 pF capacitors. This comparison of electrical standards between the regional metrology organization will establish the relationship of the capacitance unit, the farad, for national metrology institutes from several metrology regions. more...
- Published
- 2002
- Full Text
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170. Electrical Through Wafer Interconnects with 0.05 Pico Farads Parasitic Capacitance on 400µm Thick Silicon Substrate
- Author
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Ching-Hsiang Cheng, A.S. Ergun, and B.T. Khuri-Yakub
- Subjects
Materials science ,Silicon ,chemistry ,Parasitic capacitance ,business.industry ,chemistry.chemical_element ,Farad ,Optoelectronics ,Wafer ,Substrate (printing) ,business - Published
- 2002
- Full Text
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171. Miscellaneous data
- Author
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Steve Winder and Joseph J. Carr
- Subjects
Physics ,symbols.namesake ,Mathematical analysis ,Boltzmann constant ,symbols ,Farad ,Faraday constant ,Ohm ,Ampere ,Capacitance ,Characteristic impedance ,Boolean algebra - Abstract
Publisher Summary This chapter starts with a list of fundamental constants such as the Boltzmann constant, Faraday constant and gives their values. Electrical relationships are also stated. Moreover, the dimensions of various physical quantities along with fundamental units are listed. Standard units such as ampere, ampere-hour, candela, and farad are also defined. Various useful formulas which include laws of Boolean algebra, capacitance, characteristic impedance, impedance, and Ohm's law are also discussed in the chapter. more...
- Published
- 2002
- Full Text
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172. Maintenance and development of the capacitance unit at CENAM
- Author
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J.A. Moreno and R. Hanke
- Subjects
Engineering ,business.industry ,Electrical engineering ,Quantum Hall effect ,Capacitance ,law.invention ,Capacitor ,law ,Capacitance bridge ,Farad ,Ohm ,Resistor ,business ,Voltage - Abstract
Aiming to relating the Farad to the Ohm, reproduced at Centro Nacional de Metrologia (CENAM) by means of the Quantized Hall Effect (QHE), a development project was planed. The results of the construction of a capacitance bridge that constitutes the first step to achieve this objective are presented. more...
- Published
- 2000
- Full Text
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173. The Food Animal Residue Avoidance Databank (FARAD). Past, present and future
- Author
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Jim E. Riviere, Arthur L. Craigmill, Alistair I. Webb, Michael A. Payne, Ronald E. Baynes, and Stephen F. Sundlof
- Subjects
Databases, Factual ,business.industry ,Food animal ,Veterinary Drugs ,Food Contamination ,General Medicine ,Food safety ,Drug Residues ,United States ,Food Animals ,Chemical contaminants ,Farad ,Animals ,Humans ,Business ,Marketing ,Educational outreach ,Information exchange - Abstract
During the last one-and-one-half decades, FARAD has established an unparalleled compilation of residue and pharmacokinetic information for veterinary species. In order to fulfill its mission, FARAD has become as much a research project as an educational one. Pressing problems, such as disease-altered kinetics, minor-species drug use, and industrial contaminants in livestock, require the new methods of analysis FARAD is developing. The data upon which this work is based can be greatly augmented by participation by other nations. In the United States, it was the cooperation of both academic and regulatory organizations that made the success of FARAD possible. Similar international cooperation can facilitate use of the FARAD model in other countries for the economic benefit of all participants, enhancement of food safety, and promotion of animal welfare. more...
- Published
- 1999
174. Hybrid Aerocapacitor{trademark}-battery power sources
- Author
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B.J. Kraemer, M.J. Isaacson, and T.J. Laramore
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Battery (electricity) ,Engineering ,Equivalent series resistance ,business.industry ,Electrolytic cell ,Nuclear engineering ,Electrical engineering ,Energy storage ,law.invention ,Power (physics) ,Capacitor ,law ,Farad ,Hybrid power ,business - Abstract
PolyStor, Power-One, LLNL and Aerojet are participants in a Technology Reinvestment Program contract supported by the Advanced Research Project Agency for developing carbon aerogel-based Electrolytic Double Layer Capacitors (Aerocapacitors). This paper reports some recent results for organic-electrolyte Aerocapacitors developed under this contract and initial results on their use in electrolytic double layer capacitor (EDLC)-battery power sources. EDLC-battery hybrid power sources offer the potential for increased discharge time, improved low temperature performance and longer cycle life vis-a-vis batteries in pulse discharge applications. The authors previously presented performance results for AA Aerocapacitors but this is the first report of their work on hybrid power sources. Prototype organic-electrolyte Aerocapacitors exhibit low equivalent series resistance (ESR), high capacitance, excellent rate capability at room temperature and low temperatures, and long life. The AA-size devices assembled for testing have ESRs of 20-30 m{Omega} at 1000 Hz and capacitances of about 6 Farads. They are capable of being discharged at very high rates. The capacity at 15 Amps is about 71% of the capacity at 1 Amp. The capacity at 1 Amp and {minus}40{degrees}C is 57% of the room-temperature 1 Amp capacity. AA Aerocapacitors have demonstrated 32,000 cycles in cycle life testing. After an initial capacity decrease of about 17% the capacity remained almost constant between cycle 10,000 and cycle 32,000. more...
- Published
- 1997
- Full Text
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175. Lake contamination models…
- Author
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Johan C. Varekamp
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Hydrology ,Physics ,lcsh:GE1-350 ,Steady state ,Ecology ,Electromotive force ,Mathematical analysis ,lcsh:Geography. Anthropology. Recreation ,Charge (physics) ,Aquatic Science ,Electric charge ,lcsh:G ,Coulomb ,Farad ,Ohm ,Constant (mathematics) ,lcsh:GB3-5030 ,lcsh:Physical geography ,lcsh:Environmental sciences ,Water Science and Technology - Abstract
"The time to reach steady state in a perfectly mixed reservoir can be derived from the time that it takes for the term exp[-t/R] go to ≈ zero, which occurs if t = 6R, when 99.75% of Cssp has been reached (600 months in the case of the model lake)." J.C. Varekamp. 2003. Lake contamination models for evolution towards steady state. J. Limnol., 62(Suppl.1): 67-72. The above sentence deserves critical consideration on the grounds of physical and experimental arguments. In an elementary physical system where a capacitor (C farad) is fed a constant electromotive force (volt) with some resistance (R ohm), the electrical charge (q coulomb) varies over time as q = qmax (1-e-t/RC). Using this equation, we can determine the time necessary for the charge to attain some arbitrary fraction of its final value, say 0.9 qmax or 0.999 qmax. This choice is somewhat arbitrary and we must constrain it based on physical considerations. more...
- Published
- 2005
176. FARAD: A Storage System for Random Real-Time Data
- Author
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Yasunobu Kato and Takashi Totsuka
- Subjects
business.industry ,Computer science ,Real-time computing ,Computer data storage ,Farad ,Real-time data ,business - Published
- 1996
- Full Text
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177. FARAD - a storage system for random real-time data
- Author
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N. Rouse, T. Totsuka, and Y. Kato
- Subjects
Workstation ,Computer science ,business.industry ,Post-production ,law.invention ,Range (mathematics) ,Nonlinear system ,law ,Computer data storage ,Farad ,Real-time data ,business ,Computer hardware ,Random access - Abstract
The way that video and audio material is edited in post production has changed, from the so-called "traditional" editing methods, to a range of nonlinear computer based workstations. These systems offer fast access to the original data, allowing multiple versions of the same basic material to be created, and the ability to make creative and technical changes at will. The FARAD (fast random access disk) system is discussed in particular. more...
- Published
- 1996
- Full Text
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178. Scientific Notation and Powers of Ten
- Author
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Clyde N. Herrick
- Subjects
Range (mathematics) ,Scientific notation ,business.industry ,Computer science ,Electrical engineering ,Farad ,Normalized number ,Arithmetic ,Power of 10 ,Ampere ,business ,Notation ,Power (physics) - Abstract
This chapter describes the scientific notation and power of ten. The electronics engineer and technician work with both very small and very large numbers. A pico farad capacitor, a 1 MΩ resistor, or the number of electrons to pass a point to produce an ampere of current are among the range of values encountered. These numbers are impractical to write out because of the length of time and large amount of space required. The employment of scientific notation for numbers requires an understanding of the powers of ten. To simplify the mathematical operations pertaining to electronic circuits, it is important to utilize scientific notations with powers of ten. It is found that to add or subtract numbers in scientific notation, each number must have the same value of power of ten. It is observed that to multiply numbers in scientific notation the numbers are multiplied and the powers of ten are added and to divide numbers in scientific notation the numbers are divided and the power of ten of the denominator is subtracted from the power of ten of the numerator. It is noted that to raise numbers in scientific notation to a power, the numbers are raised to the power and the powers of ten are multiplied by the power. more...
- Published
- 1996
- Full Text
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179. Update on FARAD food animal drug withholding recommendations
- Author
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Scott R. R. Haskell, R. Gehring, Jim E. Riviere, Alistair I. Webb, Arthur L. Craigmill, Michael A. Payne, and Ronald E. Baynes
- Subjects
Drug ,Meat ,Databases, Factual ,General Veterinary ,business.industry ,Food animal ,media_common.quotation_subject ,Veterinary Drugs ,Drug Residues ,Biotechnology ,Consumer Product Safety ,Animals ,Medicine ,Farad ,Animal Husbandry ,business ,media_common - Published
- 2003
- Full Text
- View/download PDF
180. Development of a model of energy efficient hybrid engine towards green technology
- Author
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Ataur Rahman
- Subjects
Supercapacitor ,Engineering ,Renewable Energy, Sustainability and the Environment ,business.industry ,Electrical engineering ,DC motor ,Automotive engineering ,Power (physics) ,law.invention ,Energy conservation ,Capacitor ,Fuel Technology ,law ,Automotive Engineering ,Farad ,business ,Engine control unit ,Efficient energy use - Abstract
The main focus of this study is to develop a fuel efficient hybrid engine to operate a designed and developed urban car of weight 1.42 kN. The hybrid engine is developed by coupling a high efficient 12 volt generator with a 33.5 cc engine of power 1.18 kW @7,000 rpm. The generator starts to power the DC motor to propel the car as soon as the engine is started. The engine optimum speed is considered to be 4,000 rpm to operate the generator to power the DC motor for propelling the car on 0% slope, while it is operated at 6,000 rpm to power the vehicle on 20% slope. Two super-capacitors each of 2 Farad are equipped in parallel with the generator in order to maintain the constant power supply to the DC motors for propelling the car with speed of 35 km/h. The hybrid engine was run at 65% efficiency which is more efficient than the conventional IC engine. The energy efficient hybrid engine cut carbon dioxide (CO2) and nitrogen oxides (N2O) emission significantly. more...
- Published
- 2011
- Full Text
- View/download PDF
181. Capacitors and capacitance
- Author
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P J Chivers and John Bird
- Subjects
Materials science ,business.industry ,Electric potential energy ,Hardware_PERFORMANCEANDRELIABILITY ,Dielectric ,Capacitance ,law.invention ,Capacitor ,Electric power transmission ,Hardware_GENERAL ,law ,visual_art ,Hardware_INTEGRATEDCIRCUITS ,visual_art.visual_art_medium ,Optoelectronics ,Farad ,Ceramic ,business ,Electrical conductor ,Hardware_LOGICDESIGN - Abstract
Publisher Summary This chapter discusses the use of capacitors and capacitance. A capacitor is a device capable of storing electrical energy. Practical types of capacitor are characterised by the material used for their dielectric. The main types of capacitors are variable air, mica, paper, ceramics, plastic, and electrolytic. Every system of electrical conductors possesses capacitance. For example, there is capacitance among the conductors of overhead transmission lines and also among the wires of a telephone cable. In these examples, the capacitance is undesirable but has to be accepted, minimized or compensated for. There are other situations, such as in capacitors, where capacitance is a desirable property. The unit of capacitance is the farad F, which is defined as the capacitance of a capacitor when a p.d. of one volt appears across the plates when charged with one coulomb. more...
- Published
- 1993
- Full Text
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182. Units and Constants
- Author
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Denny K. Miu
- Subjects
Physics ,Electric field ,Coulomb ,Farad ,Volt ,Electric potential ,Atomic physics ,Ohm ,Ampere ,Magnetic field - Abstract
TABLE A.1. Fundamental and derived units. MKS CGS length meter, M 102 centimeter mass kilogram, Kg 103 gram time second, S second charge coulomb, C - force newton, N 105 dyne energy joule, J 107 erg power watt, W - current ampere, A - electric potential volt, V - electric displacement coulomb/meter2 - electric field volt/meter - magnetic field tesla, T 104 gauss magnetic flux weber, We 108 maxwell magnetic intensity ampere/meter 4π × 10-3 oersted resistance ohm, Ω - capacitance farad, F - inductance henry, H more...
- Published
- 1993
- Full Text
- View/download PDF
183. Laboratory testing of high energy density capacitors for electric vehicles
- Author
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A F Burke
- Subjects
Battery (electricity) ,Engineering ,business.product_category ,business.industry ,Electrical engineering ,Capacitance ,Energy storage ,law.invention ,Capacitor ,law ,Duty cycle ,Electric vehicle ,Farad ,business ,Voltage - Abstract
Laboratory tests of advanced, high energy density capacitors in the Battery Test Laboratory of the Idaho National Engineering Laboratory have been performed to investigate their suitability for load-leveling the battery in an electric vehicle. Two types of devices were tested -- 3 V, 70 Farad, spiral wound, carbon-based, single cell devices and 20 V, 3. 5 Farad, mixed-oxide, multi-cell bipolar devices. The energy density of the devices, based on energy stored during charge to the rated voltage, was found to be 1--2 Wh/kg, which agreed well with that claimed by the manufacturers. Constant power discharge tests were performed at power densities up to 1500 W/kg. Discharges at higher power densities could have been performed had equipment been available to maintain constant power during discharges of less than one second. It was found that the capacitance of the devices were rate dependent with the rate dependency of the carbon-based devices being higher than that of the mixed-oxide devices. The resistance of both types of devices were relatively low being 20--30 milliohms. Testing done in the study showed that the advanced high energy density capacitors can be charged and discharged over cycles (PSFUDS) which approximate the duty cycle that would be encountered more » if the devices are used to load-level the battery in an electric vehicle. Thermal tests of the advanced capacitors in an insulated environment using the PSFUDS cycle showed the devices do not overheat with their temperatures increasing only 4--5{degrees}C for tests that lasted 5--7 hours. 7 refs., 33 figs., 11 tabs. « less more...
- Published
- 1991
- Full Text
- View/download PDF
184. Simultaneous actuation and displacement sensing for electrostatic drives
- Author
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Placid M. Ferreira and Jingyan Dong
- Subjects
Engineering ,business.industry ,Mechanical Engineering ,Acoustics ,Capacitance ,Signal ,Displacement (vector) ,Electronic, Optical and Magnetic Materials ,Amplitude modulation ,Mechanics of Materials ,Electrostatic generator ,Electronic engineering ,Farad ,Electrical and Electronic Engineering ,business ,Actuator ,Phase modulation - Abstract
This paper presents a method for driving a MEMS electrostatic actuator, while simultaneously sensing the resulting displacement/capacitance without the use of an additional physical sensing structure. The approach superposes the sensing and actuation signals into a single input into the system and obtains its mechanical (displacement) response from the modulation (amplitude or phase) it produces on the sensing input. The approach is analyzed and experimentally shown to produce an amplitude modulation of 0.1857 mV µm−1 of displacement on electrostatic drive that produces a displacement of 14 µm at 100 V and a 0.55 pF capacitance change from a nominal capacitance of 0.35 Pico farads. The approach enables a very cost-effective and convenient approach to detect the displacement of MEMS devices for a variety of applications in the laboratory environment, and provide a potential feedback signal for closed-loop control of electrostatically driven MEMS devices. more...
- Published
- 2008
- Full Text
- View/download PDF
185. Capacitance measurements on small parallel plate capacitors using nanoscale impedance microscopy
- Author
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Olivier Schneegans, Rene Meyer, Frédéric Houzé, Pascal Chrétien, Laboratoire de génie électrique de Paris (LGEP), and Université Paris-Sud - Paris 11 (UP11)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Centre National de la Recherche Scientifique (CNRS) more...
- Subjects
010302 applied physics ,Materials science ,Nanostructure ,Physics and Astronomy (miscellaneous) ,Differential capacitance ,business.industry ,Analytical chemistry ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Capacitance ,law.invention ,Capacitor ,Parasitic capacitance ,Hardware_GENERAL ,law ,0103 physical sciences ,Microscopy ,Hardware_INTEGRATEDCIRCUITS ,Farad ,Optoelectronics ,0210 nano-technology ,business ,Electrical impedance ,ComputingMilieux_MISCELLANEOUS - Abstract
Capacitance values in the picofarad to femtofarad range have been measured on a set of square parallel plate capacitors using a homemade nanoscale impedance microscopy (NIM) device and compared with numerical simulations. A simple analytical model involving the main geometrical parameters is proposed, which correctly fits the experimental results. This model was validated by further measurements on rectangular electrodes and capacitors surrounded by guard rings. The edge effects and stray capacitance contribution were hence determined. Finally, the present resolution of our NIM device was estimated by imaging a tiny 8×8μm2 capacitor, confirming the relevance of such reference samples. more...
- Published
- 2007
- Full Text
- View/download PDF
186. Frequency stabilized radio-frequency generator for driving ion traps and other capacitive loads
- Author
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B. T. Chang and T. B. Mitchell
- Subjects
Generator (circuit theory) ,Materials science ,law ,Oscillation ,Capacitive sensing ,Acoustics ,Vacuum tube ,Phase (waves) ,Farad ,Radio frequency ,Instrumentation ,law.invention ,Electronic circuit - Abstract
We report the design and performance of a simple radio-frequency generator, suitable for driving capacitive loads such as ion traps in the few to thousand picofarad range. The oscillation frequency can be phase locked to an external reference oscillator, providing excellent frequency stabilization. Amplitude control circuits allow the oscillations to be rapidly started and stopped. more...
- Published
- 2006
- Full Text
- View/download PDF
187. Final report on key comparison EUROMET.EM-K4 of 10 pF and 100 pF capacitance standards
- Author
-
J H Belliss
- Subjects
Traceability ,business.industry ,Physical laboratory ,General Engineering ,Electrical engineering ,Farad ,business ,Reference standards ,Capacitance ,Metrology ,Mathematics - Abstract
This report describes a comparison of 10 pF and 100 pF capacitance standards organized within the framework of EUROMET Project No. 345 between 1995 and 1998. Piloted by the National Physical Laboratory (NPL, UK), the comparison involved sixteen national metrology institutes (NMIs), several of which are members of other regional metrology organizations, and the Bureau International des Poids et Mesures. The results show that there are significant differences between representations of the farad by some NMIs. However, the agreement demonstrated by the comparison gives confidence in maintaining traceability for the farad via either a calculable capacitor or a quantum Hall reference standard and the consensus value of the von Klitzing constant, RK-90. more...
- Published
- 2002
- Full Text
- View/download PDF
188. Non-Faradaic electrochemical sensors: principles and practice
- Author
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Andrew M. Woodward, Debra A. Williams, P. Julian Iredale, Douglas B. Kell, Nigel J. Cade, and T. Kim Gibbs
- Subjects
Permittivity ,Condensed matter physics ,Chemistry ,Electrode ,Farad ,Conductance ,Conductivity ,Capacitance ,Excitation ,Analytical Chemistry ,Electrochemical cell - Abstract
In this paper the principles of non-faradaic electrochemistry are outlined, and non-faradaic electrochemical methods are described which provide: (i) a solution to the problem of devising a real-time biomass probe; and (ii) in certain instances a means of measuring enzymic behaviour in situ. The linear, non-faradaic or 'passive' electrical properties of a biological or other system are completely characterized by its conductance (siemens) and capacitance (farads), reflecting, respectively, the inand out-of-phase portions of the alternating potential difference caused in response to the application of an alternating current. These macroscopic properties depend in part on the size and geometry of the electrodes, and reflect the intrinsic properties of the system, permittivity and conductivity (see, for example, references 1-3). For plane-parallel electrodes of area A separated by a distanced, the relationship between the conductivity a' and conductance G is a'= G(d/A), where ~d/A) is known as the cell constant and has units of length. The capacitance Cis related to the permittivity E' by E' = C(d/Ac0J, where Eo is an experimental constant equal to 8.854 x 10F m, such that a cubic electrochemical cell of unit dimensions containing water (which has a permittivity of 78.4 at 298 K) has a capacitance of some 6.94 pF. By 'linear', we mean that the measured conductance and capacitance are independent of the magnitude of the exciting field, and that excitation by a current at a frequency f Hz leads only to an alternating potential difference at the same frequency. more...
- Published
- 1991
- Full Text
- View/download PDF
189. New NBS Measurements of the Absolute Farad and Ohm
- Author
-
Robert D. Cutkosky
- Subjects
Capacitor ,Engineering ,law ,business.industry ,System of measurement ,Electrical engineering ,Farad ,Electrical and Electronic Engineering ,Ohm ,business ,Instrumentation ,Capacitance ,law.invention - Abstract
A recently completed calculable cross capacitor in conjunction with a previously described collection of ac and dc bridges has made possible a highly accurate measurement of the farad and the ohm. The cross capacitor and its auxiliary equipment, as well as those components of the measurement system which have not been covered in prior publications, are described in detail. The measurements indicate that the National Bureau of Standards (NBS) unit of capacitance is given by FNBS = 1 F + 1.787 ?F, and that the NBS unit of resistance is given by ?NBS = 1 ? - 0.819 ??. more...
- Published
- 1974
- Full Text
- View/download PDF
190. Production of the unit of capacitance
- Author
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V. V. Viktorov, I. N. Krotkov, and T. F. Frudko
- Subjects
Physics ,Inductance ,business.industry ,Applied Mathematics ,Primary standard ,Electrical engineering ,Production (economics) ,Farad ,business ,Instrumentation ,Capacitance ,Magnetic flux ,Electromagnetic induction - Abstract
The perfection of the complex of measuring means that are presently a state primary standard of the farad of the USSR have as their purpose a further decrease in the error of reproducing the farad, which must be decreased and brought to between 1·10−7 and 2·10−7. An important role, namely the perfection of indirect methods and an increase in the precision of reproducing still other electromagnetic units, was assigned to the primary standard of the unit of capacitance in the course of perfecting the system of standards of units of electrical magnitudes [4], These units include resistance, inductance, magnetic flux, and magnetic induction, whose reproduction error in the new system of standards will be decreased to between one-third and one-half. more...
- Published
- 1976
- Full Text
- View/download PDF
191. Low-frequency dielectric measurements (10-4to 6 × 104Hz): a new computer-controlled method
- Author
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B Mahboubian-Jones, R A Pethrick, M Gawayne, and D Hayward
- Subjects
Materials science ,business.industry ,General Engineering ,General Physics and Astronomy ,Dielectric ,Low frequency ,Sample (graphics) ,Dielectric response ,Optics ,Range (statistics) ,Farad ,General Materials Science ,business ,Instrumentation - Abstract
An apparatus is described which allows examination of the dielectric response of a sample over a frequency range of 10-4 to 6 × 104 Hz. The apparatus is capable of measuring loss tangents down to 10-4 for samples with capacitances of a picofarad and upwards. more...
- Published
- 1984
- Full Text
- View/download PDF
192. A Scaleable Technique for the Measurement of Intrinsic MOS Capacitance with Atto-Farad Resolution
- Author
-
J.E. Oristian, Robert W. Dutton, James T. Walker, and Hiroshi Iwai
- Subjects
Materials science ,Differential capacitance ,business.industry ,Transistor ,Electrical engineering ,Integrated circuit ,Hardware_PERFORMANCEANDRELIABILITY ,Capacitance ,Electronic, Optical and Magnetic Materials ,law.invention ,Parasitic capacitance ,Hardware_GENERAL ,law ,Hardware_INTEGRATEDCIRCUITS ,Equivalent circuit ,Optoelectronics ,Farad ,Field-effect transistor ,Capacitance probe ,Electrical and Electronic Engineering ,business ,Metal gate ,Hardware_LOGICDESIGN ,Voltage - Abstract
An on-chip capacitance measurement technique used for interline capacitances has been extended to MOS transistor capacitance measurements. The gate of the test transistor is connected to a reference capacitance made on the same chip. Small ac signals are applied to one of the transistor terminals successively. The magnitude of the ac voltages appearing on the gate node is measured indirectly. C/sub gd/,C/sub gs/ and C/sub gb/ are calculated accurately from the measured ac voltage and the reference capacitance value. It was found that C/sub gd/ and C/sub gs/, are measured completely free of parasitic capacitances resulting from both the internal on-chip circuit and external wiring. The on-chip circuit is simple and can easily be scaled down. These features insure this technique is the most suitable for the measurement of minimum-geometry transistors with atto-Farad-range resolution. It is shown that this technique has the ability to detect the capacitance difference which comes from the misalignment of source and drain metal connections. Measurements with this technique are used to first describe the short- and narrow-channel effects on MOS transistor capacitance. more...
- Published
- 1985
- Full Text
- View/download PDF
193. An alternating current bridge for comparing four-terminal-pair impedances at ω = 104 rad/s
- Author
-
R. Hanke
- Subjects
Physics ,business.industry ,Voltage divider ,Mathematical analysis ,Electrical engineering ,Time constant ,law.invention ,Terminal (electronics) ,law ,Dissipation factor ,Farad ,Electrical and Electronic Engineering ,Ohm ,business ,Alternating current ,Instrumentation ,Electrical impedance - Abstract
An AC bridge has been developed for comparing capacitances from 10 to 1000 pF and resistances from 1 to 100 kΩ with a relative uncertainty of about 6×10-8 at ω=104 rad/s using an inductive voltage divider (IVD) with a nominal ratio of 1:10. Apart from these two quantities the difference in the dissipation factor of the capacitances can be determined with an uncertainty of about 9×10-8 and the difference in the time constants of the resistances with an uncertainty of about 2×10-11 s. It is proved that the uncertainty, particularly in the measurement of capacitances and resistances, can be considerably reduced, because it mainly depends on the errors of the IVD. This bridge has been developed to derive the SI unit ohm from the SI unit farad at the Physikalisch-Technische Bundesanstalt (PTB). more...
- Published
- 1982
- Full Text
- View/download PDF
194. Food Animal Residue Avoidance Databank (FARAD): a pharmacokinetic-based information resource
- Author
-
Stephen F. Sundlof, Jim E. Riviere, and Arthur C. Craigmill
- Subjects
Pharmacology ,Meat ,General Veterinary ,Database ,Computer access ,Computer science ,Food animal ,Food Contamination ,Mycotoxins ,computer.software_genre ,United States ,Anti-Bacterial Agents ,Action levels ,Government Agencies ,Information resource ,Data file ,Information system ,Farad ,Pesticides ,computer ,Information Systems - Abstract
The Food Animal Residue Avoidance Databank (FARAD) is a pilot project funded through the USDA Extension Service. It represents a major effort to compile into a single source large amounts of information on veterinary pharmaceutics, pharmacokinetics and physiochemical properties of drugs and other chemicals used in livestock production. FARAD is a computer-based system consisting of five data and numerous command files that access the data files to facilitate rapid input and retrieval of the desired information. The data files include proprietary information on all pharmaceutical products approved for use in food animals in the United States; physicochemical information on more than 100 chemicals contained in the databank; regulatory information pertaining to tolerance and action levels of chemical residues in animal products and allowable concentrations of drugs in feed; pharmacokinetic rate and volume constants pertinent to residue depletion modeling in a variety of species; bibliographic citations to which all of the information contained in the databank is referenced. All of the information in FARAD is currently available through three regional access centers in the United States, and direct computer access to the data may become available in the future. more...
- Published
- 1986
- Full Text
- View/download PDF
195. Maximally-Flat Time Delay Ladders
- Author
-
S. Deutsch
- Subjects
Physics ,business.industry ,Mathematical analysis ,Electrical engineering ,Impulse (physics) ,Capacitance ,Omega ,Inductance ,Damping factor ,Farad ,Electrical and Electronic Engineering ,business ,Dual impedance ,Electrical impedance - Abstract
The driving-point impedance for a maximally-flat time delay response is derived. The impedance is synthesized as an infinite low-pass LC ladder that starts with an \epsilon G/\omega_0 -farad shunt capacitor The ladder elements rapidly taper toward a capacitance of 2G/\omega_0 farads and an inductance of 2R/\omega_0 henries. The impulse and step responses of the impedance are derived as a series of Bessel functions. A three-terminal maximally-flat time delay transfer impedance is also considered. The conditions for a smoothly-tapering ladder structure are given. The transfer impedance is synthesized as an infinite low-pass LC ladder whose first two shunt capacitors are 32G/(9\omega_0) and \epsilon^{3}G/(9\omega_0) farads, respectively. The impulse and step responses of the transfer impedance are also derived. more...
- Published
- 1959
- Full Text
- View/download PDF
196. Negative Resistance as a Machine Parameter
- Author
-
G. H. Fett
- Subjects
Physics ,Oscillation ,law ,Negative resistance ,General Physics and Astronomy ,Farad ,Mechanics ,LC circuit ,Moment of inertia ,Capacitance ,Voltage ,Armature (electrical engineering) ,law.invention - Abstract
A series generator in the operating range below maximum voltage possesses both d.c. negative resistance, (−V/I), and incremental negative resistance, (−dV/dI). It is shown that the incremental negative resistance is equal to Kn−R, where n is the speed, K the volts per r.p.m. per unit of field current, and R is the armature circuit resistance. Since the series generator has the incremental resistance property, it will support oscillations if the tuned circuit has the proper constants. It is shown that a generator load consisting of a separately excited motor can be represented by a condenser of sufficient size (in the order of farads), that oscillations at mechanically feasible frequencies of 0.2 to 1.5 cycles per second can be obtained. It is shown analytically that the magnitude of the capacitance varies directly with the moment of inertia of the motor armature and inversely with the square of the induction factor. It is shown experimentally that the frequency of oscillation of the circuit depends upon the motor induction factor and moment of inertia, and slightly upon the circuit resistance. The amplitude of oscillation is controlled by the circuit resistance. more...
- Published
- 1943
- Full Text
- View/download PDF
197. Continuous and Pulse Polarization off Ni in H2SO4
- Author
-
Ken Nobe and R. R. Sayano
- Subjects
Tafel equation ,Materials science ,Passivation ,Pulse (signal processing) ,Open-circuit voltage ,General Chemical Engineering ,Analytical chemistry ,chemistry.chemical_element ,General Chemistry ,Anode ,Nickel ,chemistry ,Farad ,General Materials Science ,Polarization (electrochemistry) - Abstract
The anodic behavior of Nickel 200 (99.5 percent) and Nickel 270 (99.97 percent) in 1 N H2SO4 was studied galvanostatically and potentiostatically by both continuous and pulse polarization techniques. Open circuit differential capacitances were 31 ± 2 μ farad/ cm2 for Ni 200 and 23 ± 1 μ farad/cm2 for Ni 270. Anodic Tafel slopes of 48 and 50 mv were obtained with pulse galvanostatic polarization for Nickel 200 and 270. Pseudo-passivation and secondary passivation phenomena were observed. Results indicate that the passivation parameters can be determined equally well with either continuous or pulse polarization. more...
- Published
- 1966
- Full Text
- View/download PDF
198. Discontinuity Capacitance of a Coaxial Line Terminated in a Circular Waveguide
- Author
-
E.W. Risley
- Subjects
Radiation ,Fabrication ,Materials science ,business.industry ,Electrical engineering ,Condensed Matter Physics ,Capacitance ,Conductor ,Magnetic field ,Discontinuity (geotechnical engineering) ,Farad ,Coaxial line ,Electrical and Electronic Engineering ,Atomic physics ,business ,Electrical conductor - Abstract
This calculation evaluates the discontinuity capacitance of a coaxial line terminated in a circular waveguide using the Rayleigh-Ritz variational technique. A 50-ohm 3/4-inch coaxial line termination with solid center conductor was fabricated with center and outer conductor dimensions of 0.32568/spl plusmn/ 0.00002 and 0.74995/spl plusmn/ 0.00002 inches, respectively. The measured value of capacitance of this termination at 1000 Hz was 2.164 x 10/sup -13/ farads as compared with the calculated value of 2.177093 x 10/sup -13/ farads. Calculated values of capacitance for other line sizes were also compared with measured values and in each case the calculated value agreed with the measured value to within the experimental error of the measured value. more...
- Published
- 1969
- Full Text
- View/download PDF
199. Quantometric Analysis of High Alloy (1st Report)
- Author
-
Kazuo Saito, Heiichi Mochizuki, and Masao Kawahata
- Subjects
Materials science ,Spectrometer ,Alloy ,Analytical chemistry ,chemistry.chemical_element ,Grating ,engineering.material ,Tungsten ,Capacitance ,chemistry ,Electrode ,engineering ,Farad ,Dispersion (chemistry) - Abstract
Stainless steel is quantometrically analysed by a large spectrometer fitted with a grating of high dispersion.The spectrometer is of the largest type used in quantometers;its dispersion is 3.3A/mm (1st order), yet there was some difficulty in selecting spectral lines.Feussner's spark is used for excitation with a plane-finished sample as the upper electrode and a tungsten rod as the counter electrode.12000 volts as the secondary voltage, 0.0033 micro farads as the capacitance, 20 seconds as the pre-spark time and only the residual inductance were for obtaining suitable excitation.Results are in agreement with those of chemical analysis with errors of less than 1% for Ni and Cr and less than 2% for Si, Mn, Cu and Mo.As the analysis on different kinds of stainless steel is influenced by coexisting elements, parallel working curves are prepared by using standardized samples. The error caused by variation of Fe content is corrected by multiplying set values by a coefficient. more...
- Published
- 1959
- Full Text
- View/download PDF
200. Recent Actions Taken By the Symbols, Units, and Nomenclature (S.U.N.) Committee Of the International Union of Pure and Applied Physics (I.P.U.) in Reference to C.G.S. Magnetic Units
- Author
-
Arthur E. Kennelly
- Subjects
Watt ,Engineering ,business.industry ,Electrical engineering ,Joule ,Industrial and Manufacturing Engineering ,Control and Systems Engineering ,Law ,Coulomb ,Unit of length ,Farad ,Metre ,Electrical and Electronic Engineering ,Ohm ,business ,Ampere - Abstract
In reference to the C.G.S. magnetic units, a brief historical outline is presented of the actions taken by international electrical congresses from 1893 to 1904, and by international technical and scientific unions from 1904 to 1932. Emphasis is laid on the results of the S.U.N. Committee meeting of July, 1932, as the latest development. The present status of international agreement on C.G.S. magnetic units is unofficially presented, in the light of the historical background. Turning to future possible developments, certain questions are pending for consideration, by either or both committees, in order to clear up any outstanding differences of international opinion over magnetic units in the classical C.G.S. system. In order to convert the existing series of practical electromagnetic units (ohm, volt, ampere, coulomb, farad, joule, watt, henry and pramaxwell) into a complete system, international agreement must first be reached upon the two outstanding questions: (a) Subrationalising (4? NI or NI for mmf). (b) The unit of length to be adopted (meter or cm). Suggestions are offered along both these lines. more...
- Published
- 1933
- Full Text
- View/download PDF
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