Presenting the devices invented by Toepler, Holtz, Wimshurst, and Wommelsdorf, the history of the influence machines, the progress made, and the remaining deficits are discussed. The theoretical considerations published in the literature lack generalizable statements on the efficiency. Based on R. W. Pohl's model (1927), an elementary analysis is made, with the result that the upper limit of the theoretically achievable efficiency of influence machines is only 50%.

中文翻译：

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百分之五十的机器-影响机器的简史和效率的基本理论：一次尝试

介绍由Toepler，Holtz，Wimshurst和Wommelsdorf发明的设备，讨论影响机器的历史，取得的进展以及剩余的不足。文献中发表的理论考虑缺乏关于效率的可概括性陈述。基于RW Pohl的模型（1927），进行了基础分析，结果表明，影响机器的理论上可达到的效率上限仅为50％。