I am using YFS201 flow sensors to detect the flow of water in a pipe . The response from the flow sensor is frequency and I want to convert output of flow sensor in to voltage. I have searched in Google I have got some circuit.


when I am using that I am getting only 0.2v /0.3v max.

I have used exact components for these circuits which is mentioned on above link

If you one have experienced in this frequency to voltage converter circuit please share your knowledge to me

  • \$\begingroup\$ WHICH of the 5 million, 3 hundred, and 79 schematics that search turns up did you actually build? You are aware that that sensor provides pulses at low frequencies (like, under 100Hz) and that most of the circuits you found are intended for much higher frequencies? \$\endgroup\$
    – JRE
    Jun 10, 2017 at 17:48
  • \$\begingroup\$ Sorry .kindly find the link on below \$\endgroup\$ Jun 10, 2017 at 18:06
  • \$\begingroup\$ circuitstoday.com/frequency-to-voltage-converter-using-lm331 \$\endgroup\$ Jun 10, 2017 at 18:06
  • \$\begingroup\$ The link tells you how to calculate the expected voltage for a given frequency. Have you tried calculating the voltage for pulse rate at your expected flow rate? Maybe you should be getting a voltage of 0.2V. \$\endgroup\$
    – JRE
    Jun 10, 2017 at 18:10
  • \$\begingroup\$ No I was not calculated.i have directly given output of the sensor to this circuit.when I was measuring voltage at output side it's showing 0.2 to 0.3 v only. \$\endgroup\$ Jun 10, 2017 at 18:15


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