A Compensated Thermionic Electrometer

Compton, Ken; Haring, H. E.

doi:10.1149/1.3493791

Cited by 12 publications

(9 citation statements)

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“…Numerous circuits have been published in which the delicate and relatively expensive electrometer was replaced by vacuum tubes. A recent paper by Compton and Haring (47) described a compensated thermionic electrometer which is stated to have possibilities for use with thick glass electrodes. Robertson (36) reported the use of a galvanometer of high sensitivity with electrodes of very low resistance.…”

Section: Apparatus and General Methodsmentioning

confidence: 99%

A metal-connected glass electrode

Thompson¹

1932

BUR. STAN. J. RES.

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Glass electrodes have come into extensive use for the measurement of hydrogenion activity in special cases in which other kinds of electrodes are unsuitable. Previous methods of construction have produced glass electrodes which were fragile, had an uncertain length of life, and required connecting in circuit with two standard electrodes. In the work reported in this paper a glass electrode was developed which has a comparatively thick wall and a direct metallic connection to the glass. This makes a very durable apparatus and eliminates one standard electrode from the circuit. It is shown that the accuracy of such a metal-connected glass electrode is comparable with that of other electrodes used in pH measurement. CONTENTS Page I. Introduction 833 1 Figures in parenthesis here and throughout the text refer to the numbers used in the bibliography at the end of this paper. 2 Commercial glass of this composition is obtainable, for instance, No. 015 glass of the Corning Glass Co., Corning, N. Y. Tubing with an outside diameter of 7 mm, and 1 mm wall is convenient for blowing membrane electrodes. '6.55 B. c. p.

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Section: Apparatus and General Methodsmentioning

confidence: 99%

A metal-connected glass electrode

Thompson¹

1932

BUR. STAN. J. RES.

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“…The papers that followed up on Goode’s pH meters fell into two broad categories: those that embraced its continuous-reading aspect and described improvements by using newly available tubes and/or alternative circuits − , and those that merely incorporated one or more vacuum tubes with a milliammeter instead of the usual null detector (until then: a more sensitive galvanometer, a capillary electrometer, or a four-quadrant electrometer) in otherwise traditional potentiometer designs ,− . For example, Treadwell reported that he had reproduced Goode’s results with a vacuum triode of different manufacture, and had likewise obtained a wide range of grid voltages for which the output voltage was, to within 1%, a linear function of the grid potential.…”

Section: Early Follow-upmentioning

confidence: 99%

“…These papers − also highlighted some of the difficulties with such early applications of vacuum tubes to high-impedance sources. The sockets in which those tubes were mounted sometimes leaked so much electricity (thereby reducing the input resistance of the pH meter) that Elder and Wright found it necessary to remove them, and solder their wires directly to the pins of the vacuum tube.…”

Section: Vacuum Tubes and Glass Electrodesmentioning

confidence: 99%

The Early Development of Electronic pH Meters

Hines

Levie

2010

J. Chem. Educ.

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This paper describes the early development of electronic pH meters, starting with the work of Kenneth Goode in the early 1920s, and the subsequent rapid development of electron tube technology and of more efficient pH-measuring circuits, culminating about a decade later in the production of commercially successful electronic pH meters by Cambridge Instruments, Beckman, Radiometer, and others.These early, commercially successful pH meters were nullbalance instruments requiring manual adjustments of potentiometers. The subsequent development of stable dc amplifier circuits, first with vacuum tube technology, and then with solid state electronics, led to the present availability of inexpensive yet sufficiently accurate direct-reading pH meters. These modern instruments take after the original designs of Goode, who envisioned, designed, and patented the pH meter as a directreading instrument.

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“…In all the measurements reported in this paper storage batteries were used. Many experimenters have been successful in minimizing drift by various methods of internal compensation (1,3,7,23). However, rate of drift of the present instrument remains relatively unchanged in spite of attempts of the authors to make use of such compensation methods.…”

Section: Operating Characteristicsmentioning

confidence: 98%