Vibration measurements in the 1950s

The author describes the state of development of vibration measurement for rotating machines in the period 1952 to 1957. Circuit details given, for electronics using thermionic valves. The time of semiconductor electronics, let alone integrated circuits, was yet to come and in power engineering even the electronic circuits that existed were frowned on as being inherently unreliable, and too delicate for use in machine control.<
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