Milestone-Proposal:The Discovery of the Calculable Capacitor
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Docket #:2025-17
This is a draft proposal, that has not yet been submitted. To submit this proposal, click on the edit button in toolbar above, indicated by an icon displaying a pencil on paper. At the bottom of the form, check the box that says "Submit this proposal to the IEEE History Committee for review. Only check this when the proposal is finished" and save the page.
To the proposer’s knowledge, is this achievement subject to litigation? No
Is the achievement you are proposing more than 25 years old? Yes
Is the achievement you are proposing within IEEE’s designated fields as defined by IEEE Bylaw I-104.11, namely: Engineering, Computer Sciences and Information Technology, Physical Sciences, Biological and Medical Sciences, Mathematics, Technical Communications, Education, Management, and Law and Policy. Yes
Did the achievement provide a meaningful benefit for humanity? Yes
Was it of at least regional importance? Yes
Has an IEEE Organizational Unit agreed to pay for the milestone plaque(s)? Yes
Has the IEEE Section(s) in which the plaque(s) will be located agreed to arrange the dedication ceremony? Yes
Has the IEEE Section in which the milestone is located agreed to take responsibility for the plaque after it is dedicated? Yes
Has the owner of the site agreed to have it designated as an IEEE Milestone? Yes
Year or range of years in which the achievement occurred:
1956-1957
Title of the proposed milestone:
The Discovery of the Calculable Capacitor
Plaque citation summarizing the achievement and its significance; if personal name(s) are included, such name(s) must follow the achievement itself in the citation wording: Text absolutely limited by plaque dimensions to 70 words; 60 is preferable for aesthetic reasons.
The Thompson-Lampard calculable capacitor is based on an initial experimental observation by A.M. Thompson that capacitance between opposite pairs of cylinders was independent of the diameter of the cylinders, which was later proved by D.G. Lampard in what is now the Thompson-Lampard theorem in electromagnetics. This work is now the basis of the standard capacitance used internationally.
200-250 word abstract describing the significance of the technical achievement being proposed, the person(s) involved, historical context, humanitarian and social impact, as well as any possible controversies the advocate might need to review.
The nomination is for the discovery of the Thompson-Lampard calculable capacitor. In 1956, A.M. (Mel) Thompson and W.K. Clothier investigated various geometries that might have potential for a calculable capacitor. Thompson found experimentally that the capacitance per unit length depends only on the shape of the cross-section of the cylinder. It was thought a square cylinder with faces insulated from each other; the stability could be checked by measuring the capacitance of opposite faces. They called on the mathematical expertise of a colleague, Doug. G. Lampard to calculate the capacitance of this system, and he confirmed the mean capacitance would be independent of small departures of symmetry. His calculations for other geometries were more promising, and he found other shapes gave the same capacitance per unit length. A general relation was found for a four-electrode system. Experiments were undertaken with a cross-capacitor made up of four round bars and good agreement was obtained between the calculated capacitance and the capacitance measured in relation to the then existing standards. These results confirmed the possibility of a calculable capacitor whose capacitance could be calculated from a single length measurement. Out of Lampard’s work came a theorem in electromagnetics that was detailed in a publication in 1957.
IEEE technical societies and technical councils within whose fields of interest the Milestone proposal resides.
IEEE Instrumentation and Measurement Society IEEE Antennas and Propagation Society
In what IEEE section(s) does it reside?
IEEE NSW Section
IEEE Organizational Unit(s) which have agreed to sponsor the Milestone:
IEEE Organizational Unit(s) paying for milestone plaque(s):
Unit: IEEE NSW Section
Senior Officer Name: Syed Muzahir Abbas
Unit: IEEE Instrumentation and Measurement Society
Senior Officer Name: Sergio Rapuano
IEEE Organizational Unit(s) arranging the dedication ceremony:
Unit: IEEE NSW Section
Senior Officer Name: Syed Muzahir Abbas
IEEE section(s) monitoring the plaque(s):
IEEE Section: IEEE NSW Section
IEEE Section Chair name: Syed Muzahir Abbas
Milestone proposer(s):
Proposer name: Trevor S. Bird
Proposer email: Proposer's email masked to public
Please note: your email address and contact information will be masked on the website for privacy reasons. Only IEEE History Center Staff will be able to view the email address.
Street address(es) and GPS coordinates in decimal form of the intended milestone plaque site(s):
Sydney University, F09 Madsen Building, Eastern Avenue, Camperdown Campus City Rd, Camperdown NSW 2050, Australia at Elevation: -33.888666⁰, Azimuth: 151.190114⁰
Describe briefly the intended site(s) of the milestone plaque(s). The intended site(s) must have a direct connection with the achievement (e.g. where developed, invented, tested, demonstrated, installed, or operated, etc.). A museum where a device or example of the technology is displayed, or the university where the inventor studied, are not, in themselves, sufficient connection for a milestone plaque.
Please give the address(es) of the plaque site(s) (GPS coordinates if you have them). Also please give the details of the mounting, i.e. on the outside of the building, in the ground floor entrance hall, on a plinth on the grounds, etc. If visitors to the plaque site will need to go through security, or make an appointment, please give the contact information visitors will need. The plaque is intended to be placed in the foyer of the Madsen Building
Are the original buildings extant?
The work was done by the Division of Electrotechnology CSIRO located in the Madsen Building, University Grounds, Sydney University
Details of the plaque mounting:
A suitable place to highlight the event is to locate the IEEE Milestone plaque on a wall in the foyer of the Madsen Building.
How is the site protected/secured, and in what ways is it accessible to the public?
A caretaker and university staff are present at the site.
Who is the present owner of the site(s)?
The University of Sydney.
What is the historical significance of the work (its technological, scientific, or social importance)? If personal names are included in citation, include detailed support at the end of this section preceded by "Justification for Inclusion of Name(s)". (see section 6 of Milestone Guidelines)
Please refer to the attached pdf file entitled: Significance of Calculable Capacitor
What obstacles (technical, political, geographic) needed to be overcome?
The devising of the theorem and the structure of the capacitor for easy reproduction and testing for reproduction around the world.
What features set this work apart from similar achievements?
What sets this achievement apart is that the practical accurate standard capacitor can be built, which is supported by its own theorem.
Why was the achievement successful and impactful?
The calculable capacitor allows the realization of the SI unit of capacitance, the Farad, and by use of a quadrature bridge, the SI unit of resistance, the ohm. The accuracy of these is important for industry and trade as well as science and engineering. The Thompson-Lampard theorem is one of the few theorems in electromagnetics that emerged in the latter part of the last century.
Supporting texts and citations to establish the dates, location, and importance of the achievement: Minimum of five (5), but as many as needed to support the milestone, such as patents, contemporary newspaper articles, journal articles, or chapters in scholarly books. 'Scholarly' is defined as peer-reviewed, with references, and published. You must supply the texts or excerpts themselves, not just the references. At least one of the references must be from a scholarly book or journal article. All supporting materials must be in English, or accompanied by an English translation.
Significant References including dates: [1] A.M. Thompson and D.G. Lampard, ‘A new theorem in electrostatics and its applications to calculable standards of capacitance ‘, Nature, May 12, 1956, pp. 888. [2] D.G. Lampard, ‘A new theorem in electrostatics with applications to calculable standards of capacitance’, Proceedings of the IEE - Part C: Monographs, Vol. 104, no: 6, Sept. 1957, pp. 271 – 280. [3]. J.D. Jackson, ‘A curious and useful theorem in two-dimensional electrostatics’, American J Phys., Vol. 67, no.2, 1999, pp. 107. [4] J.F.H. Wright, ‘Measurement in Australia 1938-1988: A history of Australia’s National Standards Laboratory’, CSIRO Division Applied Physics, Sydney, 1988. ISBN 10: 0643048952 [5] R.D. Cutkosky, ‘The new NBS measurements of the absolute Farad and Ohm’, IEEE Trans. Instru. Measurement, Vol. IM-23, Dec. 1974, pp. 305-309. [6] P. Gournay, N. Fletcher, L. Robertsson & M. Stock, ‘Progress on the Thompson-Lampard calculable capacitor project at BIPM’, 17th International Congress of Metrology, Dec. 2015, DOI: 10.1051/DOI: 10.1051/metrology/2015 120 01. [7] G.W. Small, & J.R. Fiander, ‘Fabrication and measurement of the main electrodes of the NMIA-BIPM calculable cross capacitors, IEEE Trans. Instru. Measurement, Vol. 60, Jul.,2011, pp. 2489-2494. [8] W.K. Clothier, ‘A Calculable Standard of Capacitance’, Metrologia, Vol. 1, No. 2, 1965, pp. 36-55. [9] T.S. Bird, ‘Capacitance theorem In electrostatics [Historically Speaking]’, IEEE Antennas Propagat. Magazine, vol. 63, no. 3, pp. 142-143, June 2021, doi: 10.1109/MAP.2021.3070741.
Supporting materials (supported formats: GIF, JPEG, PNG, PDF, DOC): All supporting materials must be in English, or if not in English, accompanied by an English translation. You must supply the texts or excerpts themselves, not just the references. For documents that are copyright-encumbered, or which you do not have rights to post, email the documents themselves to ieee-history@ieee.org. Please see the Milestone Program Guidelines for more information.
Please email a jpeg or PDF a letter in English, or with English translation, from the site owner(s) giving permission to place IEEE milestone plaque on the property, and a letter (or forwarded email) from the appropriate Section Chair supporting the Milestone application to ieee-history@ieee.org with the subject line "Attention: Milestone Administrator." Note that there are multiple texts of the letter depending on whether an IEEE organizational unit other than the section will be paying for the plaque(s).
Please recommend reviewers by emailing their names and email addresses to ieee-history@ieee.org. Please include the docket number and brief title of your proposal in the subject line of all emails.
