Non Linear output over 40Hz LM2917 F/V Converter

Hi

I'm having trouble with my LM2917 frequency to voltage converter circuit. The input into the chip is an AC sine wave signal from an anemometer. My output voltage is linear up to 40Hz but stops after this frequency. The output voltage from the chip is being fed into an ADC. Does anyone have any ideas what couFounld be causing it to become non linear after 40Hz?. Thanks in advance.

Pin 3 is not the output. Pin 4 is supposed to be connected to pin 7, have a resistor to ground and used as the output.

Fixed it. I was using a polarized 2uF capacitor instead of a non-polarized capacitor as is shown in the circuit. When i replaced it the output voltage was linear over 40Hz.

audioguru said:

Pin 3 is not the output. Pin 4 is supposed to be connected to pin 7, have a resistor to ground and used as the output.

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Tried your suggestion out of curiosity and that worked fine too.
Thanks for the tip.