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voltage divider with load question and guess

Discussion in 'General Electronics Discussion' started by ratstar, Nov 12, 2020.

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  1. ratstar

    ratstar

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    Aug 20, 2018
    My guess is its still 4.5 volts from some confounding experiments ive been doing at my battlestation. (desk). If I can finally understand this itll be a good start, since its been 4 years or so and still counting, I know im fairly behind but I keep truckin on...

    [​IMG]
     
  2. hexreader

    hexreader

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    Apr 21, 2011
    3 Volts
     
    ratstar likes this.
  3. ratstar

    ratstar

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    Aug 20, 2018
    Just to test you guys out. whats this one?
    [​IMG]
     
  4. hexreader

    hexreader

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    Apr 21, 2011
    1.8 Volts
     
    ratstar likes this.
  5. ratstar

    ratstar

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    Aug 20, 2018
    just checking... (i know you knew it was 9 volts.)
     
  6. ratstar

    ratstar

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    Aug 20, 2018
    Oh no! are u saying that at between those resistors its 1.8 volts???

    Thanks I think you just helped me then. :)
     
  7. ratstar

    ratstar

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    Aug 20, 2018
    [​IMG]
     
  8. hexreader

    hexreader

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    Apr 21, 2011
    Yes 1.8 Volts - but....

    Just like all of your other posts, you are being hopelessly unclear.

    Between which resistors? There are 4 resistors in post #3, which voltage is of interest?

    Why are there arrows drawn on your diagram? - they seem to have no relevance

    Remove the meaningless arrows and add in a voltmeter symbol to indicate the two points in the circuit where you want to know the voltage. That way I will not have to guess at what answer you might want.
     
    Last edited: Nov 12, 2020
  9. ratstar

    ratstar

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    Aug 20, 2018
    But I change my mind again. Its 9v. (on the 1.8v one) With even resistance both sides, it doesnt change the voltage balance.

    Its just where im at, at the moment... im probably wrong tho...
     
  10. hexreader

    hexreader

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    Apr 21, 2011
    OK

    Whatever makes you happy ...

    If you decide to find out the truth - google "resistors in parallel", "Ohms law", "voltage divider"
    Not Googled those for myself, but I imagine that one or more may educate

    Buy yourself a solderless breadboard - a selection of resistors, a 9V battery and a cheap multi-meter. Test out for real to verify theoretical results.

    There are many possible answers to post #3, but my second guess at the answer you might prefer is 5.4 Volts. Draw a voltmeter on the diagram if you want me to stop guessing at which answer you might prefer.

    ... and add identifiers R1, R2, R3, R4 to your diagram so that we can communicate more clearly on which resistor(s) you are discussing at any time
     
    Last edited: Nov 12, 2020
    ratstar likes this.
  11. ratstar

    ratstar

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    Aug 20, 2018
    Can I please ask for your help again - Im really screwed and dont know whats going on.

    [​IMG]

    Heres a little circuit im exploring. Im deciding where to put the wire with the 50 ohm resistor either side of the 1k resistor.

    On the right, im getting very little response from the cap.

    On the left, im getting no response at all - WHY? I was expecting it to be louder because its BEHIND (with respect to negative, RED) the resistor, so it would include it as its resistance, and not be the path of least resistance anymore, so more juice would go through the cap and LED.

    But! to be the exact opposite of what I thought, it was actually 0 response, instead of the little response I was getting on the other side closer to negative. (BLUE)

    So am I missing something???
     
    Last edited: Nov 12, 2020
  12. hexreader

    hexreader

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    Apr 21, 2011
    I do not know what is going on either

    Probably nothing. The circuit looks like nonsense to me. Wire your resistor any way you want, the circuit is still nonsense.

    This is way beyond hopeless - I give in
     
    ratstar likes this.
  13. ratstar

    ratstar

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    Aug 20, 2018
    I thought you guys were professional, and ur scared off by a little resistor diagram.

    Its behaving like complete nonsense as well... confusing as hell.
     
  14. hexreader

    hexreader

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    Apr 21, 2011
    Insulting me and other forum members is unlikely to gain you respect or help
     
    Last edited: Nov 12, 2020
  15. ratstar

    ratstar

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    Aug 20, 2018
    That wasnt an insult!!! I take back that your scared, more like you just cant be bothered with things that have no point.

    It could be a voltage reduction, im finding that is very tricky, and happens without me noticing alot!
     
  16. Harald Kapp

    Harald Kapp Moderator Moderator

    11,522
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    Nov 17, 2011
    So are we.
    And why should you? An what response to what (??) do you expect?
    What should be "louder" no speaker here to be loud at all. Even with speaker, you'll get no sound from DC without an oscillator. No oscillator in sight here.
    That's because the circuit is nonsense - at least to us.
    As usual you are unable or do not want to explain what the circuit is supposed to do and how you think it does that. How are we supposed to help if you keep vital information to yourself?

    Your sketch is hardly legible, numbers and labels barely recognizable. You sure can do better.

    I feel with you.
     
  17. Harald Kapp

    Harald Kapp Moderator Moderator

    11,522
    2,654
    Nov 17, 2011
    Then stop bothering us with things that have no point.
     
    hexreader likes this.
  18. ratstar

    ratstar

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    Aug 20, 2018
    I think its because the capacitor is discharging into the led turning it off.
    And putting a resistor in the way, is making it not happen as much.
     
  19. bertus

    bertus Moderator

    1,892
    711
    Nov 8, 2019
    Hello,

    When do you learn to draw decent schematics?
    Here I redrawn your sketch:
    ratstar_problem.png
    I used the symbols from this sheet to create the drawing:
    Electrical_symbols_library.png

    Bertus
     
    Nanren888 and ratstar like this.
  20. ratstar

    ratstar

    486
    20
    Aug 20, 2018
    The sketch is correct thank you, thats not a bad idea, I do love prints.
     
    Last edited: Nov 12, 2020
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