They can be found in almost every household. Power meters are an integral tool for measuring and managing electricity consumption. An everyday object that is easy to overlook, but which, like all historical objects, is not without its context.
Images: Daniel Jankowski
This project examined exemplary episodes from 150 years of the history of electricity through three object-historical case studies. The studies range from the Hummel meter from the 1890s, housed in a wooden casing and elaborately decorated, an AEG demonstration meter from the post-war period, to the contemporary smart meter. The authors reconstruct not only the histories of these specific objects, but also their historical significance for the development of the quantification, use, and evaluation of electricity. In doing so, they took as their starting point the objects themselves, the form in which they appear to us today, and their material properties. The visual nature in which technical knowledge is embodied in the electricity meters allowed for insights into the value that historical contemporaries attributed to the technology and the underlying knowledge of electricity and its economic utilization.
The essays collected here were produced as part of a collaboration between the Chair of the History of Science and Technology at TU Braunschweig and the Power Meter Cabinet of the Physikalisch-Technische Bundesanstalt (PTB), Germany’s national metrology institute. The texts were edited and published by Daniel Jankowski and Jakob Müller. The publication aims to give the student-authored texts an impact beyond the university. For academic research, they highlight gaps in the fields of technology and energy history. For an interested public, their compilation provides an accessible introduction to the history of power meters.
Download the full publication (in German) on TU Braunschweig’s official Open Access Server:
Preview (taken from the introduction):
The atomic clock, or, more precisely, four different atomic clocks that were commissioned between 1969 and 2009, are probably the best-known artifacts at the Physikalisch-Technische Bundesanstalt, or PTB for short. In a forest area northwest of Braunschweig’s city centre, they measure the frequency of “the absorption or emission of electromagnetic radiation” during the “transition between two atomic states.” They thus make it possible to determine the duration of one second with a degree of accuracy that could not be achieved by measuring the “period of the Earth’s rotation, let alone the oscillation period of a pendulum.”1 Since the adoption of the Time Act on 25 July 1978, the PTB has been responsible for legal timekeeping in Germany and attracts thousands of visitors every year.2 Yet it is not only seconds that are measured across the extensive grounds, situated among old trees and partly ultramodern research buildings. In the Electrical Energy Measurement Technology Division of the Electricity Department, scientists and engineers also develop innovative methods for measuring electricity. They are additionally responsible for the approval and calibration of “measuring transformers, as well as high-voltage, power, and energy measurement technology.”3
Following one of the winding roads that run through the PTB from the main entrance towards the east, one reaches the so-called Ohm-Building after a few minutes. The complex, with its characteristic red-brick facade, was constructed from 1936 onwards for the Institute for Engine Research of the Hermann Göring Aeronautical Research Establishment. Today, in addition to the PTB’s Electricity Department, it houses the Power Meter Cabinet. Entering through the main entrance and climbing the stairs of the similarly red-brick stairwell, one encounters the first display cases after only a few floors. Behind glass are power meters, assembled here as artifacts that provide an insight into different stages in the development of their technology. The exhibits in the stairwell, however, represent only a small part of the Electricity Meter Cabinet in the Ohm-Building.
Images: Daniel Jankowski
The main part of the collection is carefully distributed among several wall-mounted and corridor display cases beneath the roof of the building. Dr. Martin Kahmann, the long-standing head of the Electrical Energy Measurement Technology Division, has been studying the history of the power meter since the early 2000s and has been responsible for the Cabinet since 2003. Kahmann is something of a Swiss Army knife when it comes to the historiography and museological presentation of power metering. Taking a unique bottom-up approach, the electrical engineering PhD and editor of one of the most important handbooks in the field of electrical measurement technology has not only acquired the methods of the history of technology and science. For decades, he has also continuously developed the exhibition concept, designed the display cases, produced informational materials, and published work for both engineering and humanities audiences. As part of a collaboration with the Chair of the History of Science and Technology at TU Braunschweig, in the summer semester of 2024 he enabled a seminar group of 25 history students to conduct research directly on the objects on display.
Among other outcomes, the collaborative seminar produced three texts that, by examining the user groups of technological artifacts, explicitly challenge strongly technology-deterministic approaches to explanation and open up new perspectives on ruptures and turning points in the use and metering of electricity since the late nineteenth century. In this publication, these three texts are brought together because they not only offer object-oriented glimpses into the last 150 years of energy history. The artifacts in question are a wooden, intricately decorated model by Hummel from the 1890s, an AEG demonstration meter from the post-war period, and a contemporary smart meter. In their compilation, the texts simultaneously document ruptures, continuities, and interconnections in the history of electrification, revealed through the authors’ detailed, object-centred research. For example, early and previously little-known fields of application for the devices, or the persistence of the fundamental operating principle of power meters over almost a century.
- Bauch, Andreas: Atomare Definition der Zeiteinheit 1967–2017, in: PTB-Mitteilungen 127 (2017), S. 14; Physikalisch-Technische Bundesanstalt: Seit wann läuft die erste Atomuhr in der PTB?, https://t1p.de/hwhw4. ↩︎
- Physikalisch-Technische Bundesanstalt: Jahresbericht 2024, Braunschweig 2025, S. 45. ↩︎
- Physikalisch-Technische Bundesanstalt: Elektrische Energiemesstechnik. Fachbereich 2.3, https://t1p.de/mvppn. ↩︎