Frequency To Voltage Conversion

[cnehme]

Hi Everyone,<p>I need a little circuit that will take a 0-10000hertz input
signal and convert it to a 0-5V output. <p>The conversion has to be extremely accurate, if possible,
otherwise I will take whatever I can get for now.<p>Thank you all in advance.

[greg123]

Hey,
You could try the 9400 V/F Chip. This will output a voltage that is linear to the input frequency. Did you want the componant values as well?

[cnehme]

Basically I will require as much detail as you can provide to construct the circuit, I know how to build stuff, but I do not know much about electronis.<p>Also who makes the 9400 V/F chip ? is it easy to acquire?<p>If not will an LM2917 frequency to voltage converter do the job instead, as I can easily buy these.

[greg123]

The LM2917 Chips should do the trick. The application notes contain a small schmatic showing connection for all the componants. The best suggestion i have w/o having the chip here to breadboard (as well as the notes not having too much from the mathmatical end of it) it to calculate the resloution that you need (fmax in/voutmax) and set the circuit up. Apply the frequency and adjust the Vref pot to change the resloution to what you need. With a bit of toying around, you should be able to get it pretty close. I would breadboard this or simulate it but i do not have the chip or spice information. Hope this helps.....if not....

[cnehme]

Thanks Greg you have been very helpful, I will try this out tomorrow.<p>Thanks for your help.<p>Claude.

[greg123]

No trouble, Let me know how things work out.

[Dean Huster]

Claude, I replied to your same question on the Poptronics forum. There's a related schematic using the LM2907 (or was it the LM2917?), a common chip used for spindle speed control in old 5-1/4" disk drives and easily obtainable. The skem is at http://www.poptronics.com/forums/electr ... s/715.html<p>Dean

[cnehme]

Thanks, everyone I will keep you posted on my progress. <p>In case any of you were wondering, I need this circuit to take an input frequency(0-10khz) from a mass airflow meter that is used in vehicle fuel injection systems and linearly convert it to a voltage (0-5V) which is compatible with the engine management system in my car which runs a less efficient air measurement device.