Help me to understand transformer

Discussion in 'General Electronics Chat' started by dante_clericuzzio, Mar 28, 2016.

  1. dante_clericuzzio

    Thread Starter Member

    Mar 28, 2016
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    I am totally a newbie in electronic and i have research quite extensively regarding transformer but still i couldn't really get the exact answer for my needs. I have this transformer taken out from a printer power supply and it reads like this

    240v:6v~2A

    From what i have read this is a step down transformer from 240v to 6v at 2 amp current. What i want is to use this transformer on the reverse direction and as a step up transformer but i don't know if this is possible. And some of the other question i have as follows

    1. How to connect it to the battery in order to allow continuous current flow?
    2. There are 4 legs on the transformer which one should i connect to the positive and negative of the battery?
    3. Why won't it work when using battery?

    There was something that i read on the net it needs alternating current (AC) to power this transformer how do i get the simple AC source can the PC power supply do it? and if this does where should i connect the positive and negative of the transformer?

    This is the picture of this

    20160328_192307.jpg
    20160328_192332.jpg
     
  2. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
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    From your extensive research (which I assume must have included googling the phrase "how do transformers work") you will know that transformers only work with AC. Batteries are DC and connecting one to the transformer will only drain the battery and heat the transformer.
     
    Last edited: Mar 28, 2016
  3. dante_clericuzzio

    Thread Starter Member

    Mar 28, 2016
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    Is it possible to make a battery to an AC or what power source can supply AC can the computer power supply do it?
     
  4. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
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    All batteries are DC, is the computer power supply output AC or DC?

    It is possible to add electronics between the battery and transformer to convert the DC to AC, these devices are called inverters.
     
    Last edited: Mar 28, 2016
  5. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Just read the text on the transformer again.
    It says 6 Volts at 0.2 Amps.

    To drive the transformer you will need an AC voltage.
    A PC powersupply will give DC and can not be used directly.

    Bertus
     
  6. dante_clericuzzio

    Thread Starter Member

    Mar 28, 2016
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    How do i get an AC power source? the simplest one that i can easily find?
     
  7. bertus

    Administrator

    Apr 5, 2008
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  8. dante_clericuzzio

    Thread Starter Member

    Mar 28, 2016
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  9. dante_clericuzzio

    Thread Starter Member

    Mar 28, 2016
    147
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    I've this questioned myself using transistor and some other component to turn the battery DC into AC and make 3 volt DC 500 volt AC. But i have to thanks all for the ideas given earlier that make me lead to this answer

     
  10. WBahn

    Moderator

    Mar 31, 2012
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    No need to use big, colorful fonts. People can read the normal font just fine.

    You set up a red herring example to make a blanket claim that isn't true.

    Take the step-up transformer example from your explanation. The primary is 100 V and the output is 1000 V with a power rating of 1 kW.

    So if you turn it around, you now have a primary that is 1000 V and a secondary that is 100 V with a power rating of 1 kW. The current that flows in both windings is the same in either case.

    In your example, you are choosing to violate the ratings for reasons that have nothing to do with whether it is being used as a step-up or step-down transformer.

    Imagine taking that transformer and using it as a step-up transformer but applying only 10 V to the input. To get 1 kW you need 100 A while your output would be 100 V at 10 A, both 10x the current the winding were rated for. Yet it is still being used as a1x step-up transformer.
     
  11. Motanache

    Member

    Mar 2, 2015
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    AC not.

    If you can create a mechanical device that interrupts the circuit periodically.
    Then the transformer will work.

    At 50-60 interruptions on the second (50% Duty Cycle) will have maximum efficiency.
     
  12. EM Fields

    Active Member

    Jun 8, 2016
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    View attachment 127191
    Transformer.png
    It is possible.
    If you connect the battery across either the primary or the secondary, current will flow continuously in that winding, but will flow in the other winding only while the magnetic field is building up or decaying.
    It doesn't work that way.
    https://en.wikipedia.org/wiki/Faraday's_law_of_induction

    View attachment 103269
    View attachment 103270
    If you don't have access to a simple AC source you can do this if you want to play with the transformer, but be careful since If you're driving the low voltage primary, you could get a nasty shock from the secondary:
    Buzzer flyback.png
     
    Last edited: May 20, 2017
  13. Motanache

    Member

    Mar 2, 2015
    368
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    K1 is an ordinary relay?
     
  14. EM Fields

    Active Member

    Jun 8, 2016
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    Yes, but you have to make sure that the transformer coil's resistance is low enough to allow the relay coil to attract the relay's armature.
     
  15. nsaspook

    AAC Fanatic!

    Aug 27, 2009
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    That's going too far. Someone misread a book or made incorrect assumptions that X also means Y from the lack of knowledge that's in any engineering book about transformers.
     
    Last edited: May 20, 2017
  16. WBahn

    Moderator

    Mar 31, 2012
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    There's no justification for these sweeping claims. In point of fact, the mmasba1988 is bringing up a valid real-world issue that is usually not dealt with in books; he just is drawing too sweeping a conclusion from it.
     
  17. jkaiser20

    New Member

    Aug 9, 2016
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    Made one for science fair in '83 from car coil and hand wound magnet together with a set of points with spring removed. Fun shocking others with it. Good experiment for a kid, or anyone really.
     
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