How to build a Frequency to Voltage converter without microcontrollers

Discussion in 'Homework Help' started by Thevenin99, Mar 24, 2017.

  1. Thevenin99

    Thread Starter New Member

    Mar 23, 2017
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    1
    We are supposed to construct a Frequency to Voltage converter without using any microcontrollers, or integrated circuits. Only op amps, comparators, resistors, capacitors,inductors, voltage regulators

    We were told as an example if we input a 3khz frequency we should get 3 volts in return

    Any suggestions?
     
  2. MrChips

    Moderator

    Oct 2, 2009
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    Sounds like homework to me.
    Moved to Homework Help unless proven otherwise.
     
  3. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    9,501
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    Since this is Homework, what thoughts have you had so far for solving the problem? We can give hints, but don't do your homework for you.
     
  4. OBW0549

    Distinguished Member

    Mar 2, 2015
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    Try Googling "frequency to voltage converter."
     
  5. LesJones

    Well-Known Member

    Jan 8, 2017
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    Your question contradicts itself. You say NO integrated circuit but then you say you can use opamps. (Which will be integrated circuits unless you build them yourself using discrete components.) Another tip Google "charge pumps"

    Les.
     
  6. RBR1317

    Senior Member

    Nov 13, 2010
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    I took that to mean NO F2V IC such as the LM2907. Note that at the heart of the LM2907 is a charge pump.
     
  7. absf

    AAC Fanatic!

    Dec 29, 2010
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    Here's one with any IC. But the maths is quite involved....:)

    v2f.jpg

    And here is the link.

    Allen
     
  8. MrAl

    AAC Fanatic!

    Jun 17, 2014
    5,898
    1,255
    Hi,

    A quick example which would be the most basic F to V converter is a one shot that outputs a very narrow pulse and that pulse is integrated with a fixed time constant and some leakage. The output voltage is related to the input frequency by a constant, although the linearity may not be as good as you want because of the narrow pulse and the leakage. This is the most basic way to do it but also probably the worst way to do it too.

    You should try to figure this out too and see what makes sense to you.
     
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