Tube Voltmeter Research Articles

108. 乳房用非接触形管電圧測定器の検討

108. 乳房用非接触形管電圧測定器の検討

108.乳房用非接触形管電圧測定器の検討(第24回秋季学術大会 一般研究発表予稿集)

108.乳房用非接触形管電圧測定器の検討(第24回秋季学術大会 一般研究発表予稿集)

Measuring the root-mean-square values of random voltages with tube voltmeters

The above examples indicate that in using standard tube voltmeters for measuring root-mean-square values of noise voltages it is necessary to take into account the distribution laws of their instantaneous values. Otherwise substantial errors can be made. By using the above technique it is possible to find the required corrections for every type of voltmeter and any kind of distribution law of a stationary random process.

Design of a high impedance vacuum tube voltmeter for use in the radioisotope laboratory.

A reliable, yet simple, voltage-measuring device was needed in our Isotope Laboratory (University of Oklahoma Medical Center). On many occasions we have had to switch a scintillation or Geiger head from one counting instrument to another because of breakdown or alternative application. A high-voltage voltmeter is useful in making certain one does not exceed tube-voltage ratings when peaking in on different instruments. Most scalers and ratemeters have a series of dropping resistors in the Geiger input circuit, which will give considerable voltage drop if loaded to any degree by a low-resistance external voltage-measuring device such as a conventional voltmeter. The instrument constructed has a D.C. input resistance of 110 million ohms, so negligible drain is placed on the system to be measured. We have found it quite useful in checking high voltage on malfunctioning equipment, as well as in the repair of equipment with disabled high-voltage power supplies. Two voltage ranges are provided, and the meter ma...

Apparatus Drawings Project. Report Number 30. Atomic Beam Apparatus for Determining the Mean Free Paths of Potassium Atoms in Argon

A simple atomic beam apparatus of special pedagogic interest, developed specifically for an introductory laboratory, is described. It consists of an electrically heated oven for vaporizing metallic potassium, a slit system for collimating a beam of the neutral atoms, and a detection system for measuring the number of atoms that traverse a path through an atmosphere of argon at reduced pressure. The slit-detector separation can be varied from about 2 to 20 cm. The system pressure can be adjusted from about 5×10−4 mm Hg to 5×10−6 mm Hg, and is determined with a conventional ionization gauge. The ion gauge control circuits, as well as the vacuum tube voltmeter for measuring the detector output, are low-cost “home-made” units. The relatively low-cost glass-metal apparatus is evacuated with a small 2-stage oil diffusion pump, and was designed to be operated with a minimum of maintenance. Eight pieces of the apparatus have been in regular use for four years. Detailed information on construction of the basic apparatus and the ancillary electronic equipment is given.

A low-cost recording ionization vacuum gauge

Recently available low-cost recording meters have been incorporated in a simple differential vacuum tube voltmeter circuit calibrated to read ion currents in conventional vacuum gauges. The circuit has proved useful for monitoring pressure changes in a gettered high-vacuum system and should have application for instruction purposes. Recording times up to thirty-one days per roll chart are possible and pressure indications as low as 10 −9 mmHg are obtainable. The details of circuit wiring are described along with possible applications as a sensitive current meter. The manner in which evaporated molybdenum films reduce the pressure in a field emission vacuum system is given as an illustration of the use of this circuit. The action of molybdenum getters is well known and serves as an excellent example of the application for the recording ionization gauge to problems of slow changes in pressure in a vacuum system.

Sweating and the electric resistance of the skin

Variations in the electric resistance of the skin (ESR) in relation to sweating were investigated in summer, autumn, and winter. A vacuum-tube voltmeter was used for measurements of ohm-resistance between two silver electrodes which were attached to the skin surface close together, with conductive paste. Concentration of saline solution contained in conductive paste was found to be an important factor affecting the mode of variations in ESR with changes in the rate of sweating. The most significant phenomenon we observed was that, in a hot environment, ESR on areas other than the palm of the hand decreased with depression of sweating only when measured with conductive paste containing saline solution of a high concentration. ESR on the palm, or that on any are of the body surface measured with conductive paste containing saline solution of a low concentration, increased with depression of sweating and decreased with enhancement of sweating. The effect of the season and that of a hot bath on ESR were observed. Possible mechanisms involved in variations of ESR are discussed.

On the Influence of the Gamma-Irradiation upon the Electric Conductivity of Glasses

Influence of gamma-irradiation upon properties of glasses have scarcely been studies excepting phenomena such as coloration and fluorescence caused by the irradiation. In this study, therefore, not only the influence of gamma-irradiation upon the electric conductivity of glasses, but applicability of glasses exposed by gamma-rays to semi-conductive glass or radiationdosimeter was studied.The electric conductivity for ten kinds of glasses were measured after irradiating gamma-rays up to the maximum dosage of 107r. using Co60.For the measurement of the electric conductivity, a vacuum tube voltmeter was used for the range of low resistance values and a vibration reed electrometer for the range of high resistance.The result of the measurement showed that no change in electric conductivity of the glasses occured by the irradiation of 107r. and consequently the gamma-irradiation to the glasses was found to be unapplicable in making semi-conductive glass and glass-dosimeter.

On Frequency Response Curves in Rooms. Comparison of Experimental, Theoretical, and Monte Carlo Results for the Average Frequency Spacing between Maxima

The average frequency spacing 〈Δfmax〉 between adjacent maxima of the frequency response curve between two points in a room is determined by experiment, theory, and Monte Carlo computation. In earlier papers it had been shown that, above a certain critical frequency, 〈Δfmax〉 is reciprocally related to reverberation time and not dependent on other room characteristics—disproving a belief that 〈Δfmax〉 is a useful measure of the acoustical quality of rooms. Theory predicts 〈Δfmax〉 = 3.91/T60, where T60 is the reverberation time. Monte Carlo computation gives 3.90/T60. Measurements in two very different rooms using a vacuum tube voltmeter for reading the sound pressure are in good agreement with these predictions. Measurements with a logarithmic level recorder give, as in earlier investigations, much larger values. The discrepancy cannot be explained by the level recorder's 0.5-db quantization. This paper shows that: (1) The Monte Carlo method is a useful tool for solving complex problems in room acoustics. (2) Level recorder measurements of frequency (or space) irregularities of rooms must be taken with several grains of salt.

Electrode potentials with a vacuum tube voltmeter

Electrode potentials with a vacuum tube voltmeter

Precision tube voltmeter for comparative measurements

The simple method, justified theoretically in this article and verified in practice, of improving the linearity of tube voltmeters by a better setting of the zero, permits one to use mass-produced dc instruments without any recalibration of the scale, which is especially important when a recording instrument whose recalibration is difficult is used at the output of the voltmeter.

Fluoroscopic pulmonary densiography.

Kourilsky and MarchaP presented papers at the Fourth International Congress on Disease of the Chest which stated an accuracy of 90 and 95 per cent in the diagnosis of bronchogenic carcinoma by their technique of fluoroscopic densiography. They have also reported on the use of their methods as a means of differential pulmonary function study.2 This study was undertaken because their methods appeared to offer promise of recognition of localized pulmonary disease and areas of localized dysfunction. Method A photomultiplier tube with a sodium iodide crystal is exposed to the fluoroscopic beam after passage through the chest by means of an orifice 3/32 inch in diameter and 1/8 inch long. The system is centered on the x-ray tube and mounted on the patient side of the fluoroscopic screen. The output of the tube is filtered, the impedances matched, and recorded photographically by a mirror galvanometer. Improvements in the circuitry are being made so that presentation of details will be made at an appropriate stage in the work (Fig. 1). The direct current output is measured by a damped vacuum tube voltmeter both with and without the patient. The fluoroscopic density is the percentage drop in voltage between the output with and without the patient. The variation in the output is recorded as an indication of the volume change of the chest due to respiration. The fluoroscope is adjusted to 80 kilovolts and 1.5 milliamperes which delivers 1.5 roentgens per minute at the table top.

Studies on Tablets. IV. Frictional Electrification of Crystalline Medicines.

The frictional electrification of 6 inorganic and 13 organic medicinal crystals was examined. The crystal was slid down on flat-bottomed chute into a Faraday cylinder and the induced voltage was determined by a vacuum tube voltmeter with a very small leakage of 10-13 to 10-14 A. The prediction of the phenomenon was very difficult since the sign and the amount of charge was determined by the experimental conditions, but the following tendencies were found. 1) The charge found at the chute made of paraffin paper was larger than the one made of metal or glass. The grounding of the metal chute was not effective on avoiding frictional electrification. 2) A relatively small charge was found with water-soluble crystals and a larger one with water-insoluble crystals. 3) Acetanilide, acetophenetidine, and benzoic acid behaved quite differently, i.e. negative charges and then positive charges were found on the crystals in the chute experiment. It was evidenced that this was caused by the adhesion of crystal. 4) In the treatment of crystals with surfactant, the development of charge was reduced to about 1/100 with the combination of Aspirin-Tween 40-paraffin paper chute, but an opposite charges was observed in some cases.

The Electrochemical Study on the Corrosion of Refractory by Molten Glass (1)

A systematic study on the E. M. F. between simple oxides and common glasses was carried out using a vacuum tube voltmeter for the cell Pt/solid oxide/glass melt/Pt set in a Pt ribbon resistance furnace.Sodium silicate, potassium silicate, commercial window glass, lead glass, and borosilicate glass were used. All these glasses, except the window glass, were melted from pure materials in Pt-crucible. Solid oxides used were kaolin, SiO2, Al2O3, ZrO2, CaO, MgO, BaO, ZnO etc. Two types of solid oxide electrode were used. One was a Pt wire covered with a thin layer of a solid oxide being essentially the same as that used by Plumat, and the other was a small sintered rod whose one end was wound with Pt wire. The latter showed as good results as the former, provided that good contact was assured between Pt wire and the oxide rod.Factors influencing the E. M. F. of above cells would certainly include (1) temperature distribution in the cell, (2) atmosphere, (3) oxgen pressure inside the molten glass. The effect of the factor (3) was investigated and was confirmed as being most influential.Cell: Pt/kaolin/window glass/Pt was studied. It was confirmed that the change of the structure of kaolin took place during the preheating of the electrode and the kind of the cation absorbed in kaolin affected the E. M. F. greatly, though this problem ought to be studied more closely.For the cells “Pt/simple oxide/glass melt/Pt” all mesaurements were carried out at 1000°C, because it has been reported that the temperature itself has little effect upon the E. M. F. of above mentioned cells in the temperature range from 900°C to 1300°C.The E. M. F. of these cells suggested that the radius (r:A) and the number of electric charge of the cation of the solid oxide electrode (z) have some relations to the EM. F. of the cell. For each glass the E. M. F. values were plotted against the parameter (r/z). The figure showed that the E. M. F. of oxide electrodes come upon a linear line. The plot for ZnO failed to fit on the line in many cases, which may probably be interpreted by the non rare gas type electronic structure of Zn++. According to the figures (8-12) the straight lines may be represented by the equation, V=A-B (r/z), whereV is E. M. F. (volt), A and B are the constants for each glass.As B in above equation has nearly equal value for all glasses, suggesting that the electric charge was carried by same kind of cation. It will be possible to replace B by c(zc/rc) and obtain the equation in the following form, V=A-c(zc/rc)/(z/r), where zc is the number of charge of the cation carrying the electric charge in molten glass, rc the radius of cation, and c a constant representing the type of glass.

Effect of higher harmonics in the measured voltage on the reading of a tube voltmeter with an exponential characteristic

Effect of higher harmonics in the measured voltage on the reading of a tube voltmeter with an exponential characteristic

Measurement of thickness report and new vacuum tube voltmeters described

Measurement of thickness report and new vacuum tube voltmeters described

A Sensitive System for the Measurement of Brain Responses in the Intact Human

An all-electronic method is described whereby minute electrical responses in brain recordings can be measured reliably even in the presence of large noise-to-signal ratios. The signal in this instance is a discrete response to a controlled stimulus. The ``noise'' is not white noise in this case, but the normal rhythmic activity of the electroencephalogram (EEG) which is randomly related to the signal. The responses are usually invisible in the EEG recording but they can be detected by means of averaging and storing techniques. The system makes use of gated integrators and floating-grid vacuum-tube voltmeters.

非分極性電極を用いた矩形電気泳動速度測定装置

This paper reports a modified electrophoresis apparatus by the microscopic method in the surface electrochemical study of flotation.After examining the apparatus with platinum electrodes in all its aspects, an acrylite new apparatus with non-polarizable calomel electrodes as the working electrodes so as to avoid polarization was designed and was proved satisfactory for use. Cell dimension was 2.108mm in depth, 19.87mm in width and 200mm in length, and electrophoresis was measured at the stationary level so that electroosmotic flow was zero. Field strength was measured by the vacuum tube voltmeter by putting the small calomel electrodes in the cell.By considering the theoretical equation on the electroosmotic flow in the cell, derived by Komagata, it was found that ratio of width to depth of the cell must be more than 5, and the deviation in the focusing point is discussed. Effects of the settling of particles during the mobility measurement and of particle size were also considered, and it was concluded that the former is negligible small when measured under the condition in which particles are observed within the focusing depth, and that the most suitable particle size is less than about 2μ in diameter.A mobility of -1.07μ/sec/V/cm in distilled water at 25°C was observed on the sphalerite sample and the calculated electrokinetic zeta potential was -14mV.

Seismic Level Recorder

The seismic level recorder is a sensitive recording ac vacuum tube voltmeter. The prime intention in the design of this recorder was to provide a portable level data system which could be left operating unattended for long periods of time. The seismic level recorder incorporates a high gain seismic amplifier connected to a peak-to-peak rectifier whose output is fed through a logarithmic driver to an Esterline-Angus ink recorder. The frequency response is 1 to 100 cps at the 6 db points. Provisions have been made for plugin 12 db octave band-pass filters. The calibrated scale covers approximately a 50-db range of signals allowing a wide variety of detectors and signals to be explored. (Parts of this work were supported by Tri-service Contract No. DA-36-039-sc-52654.)

A transistorized decade amplifier for low-level audio-frequency applications

The amplifier descrbied in this paper has an input resistance of approximately 400,000 ohms in the audio-frequency range. The output noise level is equivalent to 5 µv at the input terminals with a response that is down 3 db at 5 cycles and at 100 kc. The amplifier has been designed in a self-contained package, the size of a frozen orange juice can suitable for plugging into the standard banana plug terminals of a sensitive vacuum tube voltmeter. The design may be modified, with considerable reduction in volume, to incorporate the amplifier in a small package with a low signal source.