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Hello, i need help with lab equipment for electrochemical harvesting of microalgae

  1. Sep 6, 2016 #1
    Hello, i'm an Aquaculture Engineering student at lima. I'm trying to do an experiment of electrochemical harvesting of microalgae. But it seems my weakness at physics its getting in the way plus i dont know to well how to operate the equipment wich none knows either since its new to the lab. I have a DC Power supply conected to a function generator(utg9010c) (Both are Uni-T) that goes to carbon electrodes in the harvesting chamber (liquid). When i turn on the ´power supply i can modify the voltage but current seems not getting througth since the amps dont vary in the power supply. and the function generator doesn't vary the voltage when i change it in the power supply. it is supose to read in the function generator the voltage i'm applying at the liquid. and the liquid seems like its not getting any current. Does anyona have experience with this kind of equipment?

    The objective of the experiment its electrofloculation of microalgae with the carbon electrodes with specifics duty cycles and current.
    Sorry if my english its no good :(
  2. jcsd
  3. Sep 6, 2016 #2


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    Staff: Mentor

    Welcome to the PF.

    Can you show us how you are trying to use the power supply and signal generator in your setup? What DC voltage are you using? Are you trying to use the signal generator instead of a polarity inverting switch?

    BTW, the correct spelling appears to be electroflocculation. :smile:


  4. Sep 6, 2016 #3


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    Science Advisor

    Is there salt in your water?
    Maybe your conductivity is too low for much current to flow.
  5. Sep 6, 2016 #4
    Thanks berkeman, yes it's electroflocculation, thanks for the notice,

    i have a picture here of the setup


    when i turn on the equipment and put voltage even to 14 volts it seems nothing happening, the frequancy was 880 Hz, i dunno if still is too low, i've seen some videos of people doing water electrolysis even with pencils and 9volts bateries.

    When i turn up the voltage in the signal generator doens't vary the voltage. i assume it will vary as i change it in the power supply.
    Last edited by a moderator: Sep 8, 2016
  6. Sep 6, 2016 #5
    Thanks BillTre
    Maybe... But shouldn´t even do water electrolysis? i haven't use the microalgae since i wanted to try first with the water so i don´t waste the culture since i have a limited volume. Although microalgae has 35ppt salinity.
  7. Sep 6, 2016 #6


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    What is your conductivity with and without the algae?
    Salt will make the water much more conductive. Its part of your circuit.
  8. Sep 7, 2016 #7


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    I could not find an instruction manual for the function generator, it seems to be a discontinued model. I did find many pictures and the specifications on different websites. Here is my understanding of the problem.

    1) The connection between the power supply and the function generator looks wrong. The connection on the generator is an input to read the frequency of an external signal and does not change the the output of the function generator.

    2) If you tell us the model of the power supply, maybe some data on it can be found.

    3) What are the specified duty cycles and current that you need?

    4) The function generator can supply up to 20 Volts peak-to-peak and can offset that voltage up to + or - 10 Volts DC. The maximum output power is 2 Watts. The output impedance is 50 Ohms (acts like a perfect voltage source with a 50 Ohm resistor in series with the output).

    The power supply may not be needed depending on the experiment voltage and current needs.
  9. Sep 8, 2016 #8
    It seems the function generator is damaged:frown:. Last thing i would expect since its newo_O. A friend used a multitester to measure the voltage coming from the output. we test the power supply and its fine, but the function generator says 20 volts and the output gives zero. I´ll go to the seller so he can check it properly. Thanks to everyone!!!:sorry:
  10. Sep 8, 2016 #9


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    Staff: Mentor

    It's still not clear to me how you are wanting to connect a DC power supply and a signal generator to form your excitation signal for the electrodes. Are you trying to create a more powerful AC signal somehow with the combination? If you connect those pieces of lab equipment together incorrectly, it's certainly possible to damege one or both of them.
  11. Sep 10, 2016 #10
    I'm tring to compare de harvesting at diferent duty cycles ans Currents, since the original experiment its conected same way with similar equipment i try these same setting.

  12. Sep 11, 2016 #11


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    Gold Member

    The input terminal is rated for 5V max. Putting 14V on that input likely damaged the unit.

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