Sensors and Transducers: Frequency Output Versus Voltage Output

Separate types of frequency transducers, for example, string tensometers or induction tachometers, were known for many years ago. So, for example, patents for string distant thermometer (Pat. No.61727, USSR, Davydenkov N., Yakutovich M.) and string distant tensometer (Pat. No. 21525, USSR, Golovachov D., Davydenkov N., Yakutovich M.) were obtained in 1930 and 1931 accordingly. However, the output frequency of such sensors (before digital frequency counters appeared) was measured by analogue methods and consequently substantial benefit from the usage of frequency output sensors practically has not been achieved [1].