Negative Resistance and Devices for Obtaining It

Herold, E.W.

doi:10.1109/jrproc.1935.227271

Cited by 36 publications

(6 citation statements)

References 9 publications

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“…As noted in the previous paper [1] the use of two photoelectric cells (differing greatly in spectral response) and four filters gives eight conditions for establishing the shape of the spectrnl-energy , The writers are indehted to F. W. Dunmore for calling attention to this newly developed radio tube, which had escaped their -notice, although a description ot the device was published some time ago [4]. …”

Section: Distribution Of Energy In the Extreme Ultra-violet Of Thmentioning

confidence: 91%

“…Consideration was then given to other methods of producing an audio-frequency signal, including the use of a leaky triode previously used by one of the writers [3] for the production of a change in pitch of the sound in a telephone receiver, when used in connection with a photoelectric cell. In tIllS connection our attention was called to the use, by Herold [4], of a standard radio tube (type 57) in place of a neon tube to produce an audio frequency.…”

Section: A Meter For Determining the Ultraviolet Solar Spectral-mentioning

confidence: 99%

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Distribution of the energy in the extreme ultraviolet of the solar spectrum

Coblentz¹,

Stair²

1936

J. RES. NATL. BUR. STAN.

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Supplementing the data given in a previous publication (NBS R esearch Paper RP877), the present paper gives further calculations and graphs showing the distribution of energy in the extreme ultraviolet of the solar spectrum, for various air masses traversed by the rays, at a sea-level station (Washington); also the spectral-energy distribution of solar radiation outside the earth's atmosphere, showing that there is no similarity with the radiation of a black body at 6,000° li, which is sometimes used in calculating the ultraviolet solar spectral energy.The second part of the paper describes progress made in assembling apparatus for measuring the spectral q uality and total intensity of ultraviolet solar radiation by means of a photoelectric cell and filter radiometer transported aloft in sounding balloons. CONTENTS Page

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Section: Distribution Of Energy In the Extreme Ultra-violet Of Thmentioning

confidence: 91%

Section: A Meter For Determining the Ultraviolet Solar Spectral-mentioning

confidence: 99%

Distribution of the energy in the extreme ultraviolet of the solar spectrum

Coblentz¹,

Stair²

1936

J. RES. NATL. BUR. STAN.

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“…The negative transconductance circuit described by Herold [8] (of the voltage-controlled type), was adapted to this purpose since it provided a light-weight audio-frequency oscillator in which the generated frequency is approximately inversely proportional to the grid-circuit resistance. With this translating means, electrical devices having inherent resistance variation as a function of some phenomenon may be connected directly in the grid circuit, while the deflection of a mechanical instrument responsive to some phenomenon is readily converted into the variation of a grid-circuit resistor.…”

Section: Basis Of Our Methodsmentioning

confidence: 99%

A method for the investigation of upper-air phenomena and its application to radio meteorography

Diamond¹,

Hinman²,

Dunmore³

1938

J. Res. Natl. Inst. Stand. Technol.

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Experimental work conducted for the U. S. Navy Department on the development of a radio meteorograph for sending down from unmanned balloons information on upper-air pressures, temperatures, and humidities, has led to radio methods applicable to the study of a large class of upper-air phenomena. The miniature transmitter sent aloft on the small balloon employs an ultrahighfrequency oscillator and a modulating oscillator; the frequency of the latter is controlled by resistors connected in its grid circuit. These may be ordinary resistors mechanically varied by instruments responding to the phenomena being investigated, or special devices the electrical resistances of which vary with the phenomena. The modulation frequency is thus a measure of the phenomenon studied. Several 'phenomena may be measured successively, the corresponding resistors being switched into circuit in sequence by an air-pressure-driven switching unit. This unit also serves for indicating the balloon altitude. At the ground receiving station, a graphic frequency recorder, connected in the receiving set output, provides an automatic chart of the variation of the phenomena with altitude.

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“…This allows for smaller devices (as there are no sweep coils required) and exploration of a greater range of fields than can be achieved by retuning field sweep oscillators. In a 1951 paper by Knoebel [30], a transitron oscillator is used [31] that utilizes a minimal number of components (see Figure 12) to generate oscillations. The oscillation frequency of such a circuit can be controlled by a single capacitor, allowing for simple tuning of such a device although the final circuit deployed to facilitate the measurement of the resonant frequency of the sample is significantly more complicated.…”

Section: Oscillator Circuits Using Frequency Sweepmentioning

confidence: 99%

Advances in Electronics Prompt a Fresh Look at Continuous Wave (CW) Nuclear Magnetic Resonance (NMR)

2017

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Continuous Wave Nuclear Magnetic Resonance (CW-NMR) was a popular method for sample interrogation at the birth of magnetic resonance but has since been overlooked by most in favor of the now more popular pulsed techniques. CW-NMR requires relatively simple electronics although, for most designs, the execution is critical to the successful implementation and sensitivity of the system. For decades there have been reports in the literature from academic groups showing the potential of magnetic resonance relaxation time measurements in industrial applications such as the production of food and drink. However, the cost, complexity and power consumption of pulsed techniques have largely consigned these to the literature. Advances in electronics and developments in permanent magnet technology now require a fresh look at CW-NMR to see if it is capable of providing cost effective industrial solutions. In this article, we review the electronics that are needed to undertake a continuous wave NMR experiment starting with early designs and journeying through the literature to understand the basic designs and limitations. We then review the more recent developments in this area and present an outlook for future work in the hope that more of the scientific community will take a fresh look at CW-NMR as a viable and powerful low-cost measurement technique.

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Negative Resistance and Devices for Obtaining It

Cited by 36 publications

References 9 publications

Distribution of the energy in the extreme ultraviolet of the solar spectrum

Distribution of the energy in the extreme ultraviolet of the solar spectrum

A method for the investigation of upper-air phenomena and its application to radio meteorography

Advances in Electronics Prompt a Fresh Look at Continuous Wave (CW) Nuclear Magnetic Resonance (NMR)

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