frequency to voltage conversion

[ckdckd]

Hi all,

pls help me to design a frequency to voltage converter with low frequency give high analog voltage and high frequency give low analog voltage.
e.g A 50Hz-1KHz sqare wave will output of 3V to 2V.

 

[crutschow]

How about an LM2907 or an LM2917? The data sheet should tell you all you need to know.

 

[OlPhart]

Freq->volt converter (LM2907), test for voltage at both freq limits. Use resistor divider and/or an opamp to rescale to range desired. Use another opamp as inverter. It's the rescaling where you have to get "creative"... <<<)))

 

[ulipollo]

Ne567

 

[ckdckd]

thanks for your reply.
pls give me some circuit ref for following parameters

f->v converter gives 2V to 3V at input of 50hz to 500hz. then using an opamp inverter i ve to make this 3V to 2V. my basic concern how to make a inversion.

whether it is possible in a f->v converter who gives descending voltage o/p with ascending frequency input or i ve to use another inversion ckt.

pls suggest some ckt.

thanks

 

[ericgibbs]

thanks for your reply.
pls give me some circuit ref for following parameters

f->v converter gives 2V to 3V at input of 50hz to 500hz. then using an opamp inverter i ve to make this 3V to 2V. my basic concern how to make a inversion.

whether it is possible in a f->v converter who gives descending voltage o/p with ascending frequency input or i ve to use another inversion ckt.

pls suggest some ckt.

thanks

hi,
Look at this option, uses a LM2917 and dual CD3240 OPA, powered from a single 12Vdc supply.

50Hz in = 3Vdc out,,, 500Hz in = 2Vdc out.

Span and Offset pot adjustment.

 

[alec_t]

Check this link for an op-amp inverter:-
https://www.electro-tech-online.com/threads/basic-opamp-circuits.35258/

One op-amp should be enough to do the scaling, level-shifting and inversion.

 

[ericgibbs]

Check this link for an op-amp inverter:-
https://www.electro-tech-online.com/threads/basic-opamp-circuits.35258/

One op-amp should be enough to do the scaling, level-shifting and inversion.

alec,
Thats an AC coupled OPA circuit.????

Would be interested to see your F2V circuit based on that method.

 

[alec_t]

Thats an AC coupled OPA circuit.

Oops. That will teach me not to copy links without checking the target!
But I wasn't suggesting the F2V bit could be done with only one op-amp; just the processing of the V output.

 

[ericgibbs]

Oops. That will teach me not to copy links without checking the target!
But I wasn't suggesting the F2V bit could be done with only one op-amp; just the processing of the V output.

alec,
Thats what I suspected, you have Sunday dinner on your mind...

Attached is the asc file, if you want to play.

The LM2907/17 is at YLTS group page.

 

[alec_t]

Thanks, Eric. And there's me thinking you'd be playing with configuring the LM331 for this!

 

[ckdckd]

many thanks ericgibbs. you ve given exactly what i want. I implemented the ckt and working well.

 

[ericgibbs]

many thanks ericgibbs. you ve given exactly what i want. I implemented the ckt and working well.

hi
Thanks for letting us know its OK.

Most times when we post a circuit we don't get any feedback from the user.