How do you stepup voltage without a transformer or battery cel?

Discussion in 'General Electronics Chat' started by MarkSimms, Apr 10, 2016.

  1. MarkSimms

    Thread Starter Member

    Apr 6, 2016
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    How do you stepup voltage without a transformer or battery cel? just using basic componants, I'm looking at different small DC circuits using different voltages like a 12v circuit from a 5v circuit, mostly I just want to know how?
     
  2. OBW0549

    Well-Known Member

    Mar 2, 2015
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    What you're after is commonly called a "charge pump." Google on "charge pump circuit" and you'll get all kinds of good stuff; here's a decent tutorial.
     
  3. MarkSimms

    Thread Starter Member

    Apr 6, 2016
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    thanks
     
  4. andrewmm

    Member

    Feb 25, 2011
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    A basic component could be a dc:dc converter .. search your favourite component supplier.

    but agree, a charge pump is basically what's required.
     
  5. MarkSimms

    Thread Starter Member

    Apr 6, 2016
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    thanks

    am I right in thinking a battery cell in seres would work to step the voltage up, I took it as correct, but now I'm not sure?
     
  6. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    A battery could work, but usually there is an inductor switched in and out to get a rise in voltage.

    Google boost converter and you will see many examples.
     
  7. MarkSimms

    Thread Starter Member

    Apr 6, 2016
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    thanks
     
  8. takao21203

    Distinguished Member

    Apr 28, 2012
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    charge pump is inconvenient for large increase in voltage or large current.
    You need low ESR capacitor and switching devices with low resistance.
    Or you cant get large current.

    something like 5 to 12v at 0.5A is not really possible with small cheap parts.
     
  9. pebe

    AAC Fanatic!

    Oct 11, 2004
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  10. MarkSimms

    Thread Starter Member

    Apr 6, 2016
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    If I went with adding a small battery cel, would the circuit still work after time , or will the battery discharge and open circuit, can the current pass through a discharged battery?
     
  11. #12

    Expert

    Nov 30, 2010
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    All batteries go bad after some time. In a few cases, you can get about 5 years out of a battery.
    Now, would you like to give enough information to get answers that are better than guesses?
    Or should we just imagine what kind of circuit you're talking about and how much current it needs?
     
  12. MarkSimms

    Thread Starter Member

    Apr 6, 2016
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    Hi, I have wondered how to do it for some time for small circuits stepped up to a car 12v battery, but are you saying a non-rechargeable battery in series will boost the voltage in the circuit for 5 years? the battery I'm adding would be a plain 1.5 volt torch type battery
     
  13. #12

    Expert

    Nov 30, 2010
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    No, I'm saying you are not giving enough information to know how long a battery might last.
     
  14. MarkSimms

    Thread Starter Member

    Apr 6, 2016
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    Ok, I am thinking of 5v 1Amp or 9v 1Amp Max put in series with a couple of 1.5v AA batteries or something like that, running from a car 12v battery. But your answers speak for themselves by questioning me what the amps through the batteries are thankyou.

    so if the batteries amp drain is within the limit of the batteries, and EG a 5v Raspberry PI with 2mps of usb usage, I want to run of a 12v car battery?
     
  15. #12

    Expert

    Nov 30, 2010
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    I find it difficult to understand your sentences, but I will keep trying.
    The AA batteries will not survive a 1 amp load for more than a minute or so.
    If a car battery has 12 volts and the Raspberry needs 5 volts, you do not need to boost the voltage up from 12 volts to 5 volts. You need to reduce the voltage. We use a voltage regulator to do that. Some of them only need 3 or 4 parts.
     
    Roderick Young likes this.
  16. Roderick Young

    Member

    Feb 22, 2015
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    Excellent answer, and I salute the patience on #12's part. I agree, what you need is a step-down arrangement. You can find a little adapter that plugs into the cigarette lighter and puts out USB at 2.1 amps. That's probably your best bet, and you can just use a regular micro-USB cable to power your Pi in that case. If the 12V battery is outside of a car, you can rewire the adapter to make the right connection.

    Here's one. I don't vouch for the seller, just showing it as an example. http://www.ebay.com/itm/4x-Dual-2-1...481925?hash=item3d153f67c5:g:o1AAAOSwcdBWRQwh

    Stepping down voltage in usually easier than stepping it up. Like if you have too much money, it's easy to have less. But if you have too little, it's hard to have more.
     
  17. cmartinez

    AAC Fanatic!

    Jan 17, 2007
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    Mark, as has already been said in previous posts, it would be really helpful if your were to tell us in detail what it is that you specifically want to do.
     
  18. MarkSimms

    Thread Starter Member

    Apr 6, 2016
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    I'm sorry I have given a bad example, as I was trying to give you an example because you needed hard facts, the fact is I just want to know how you step up a 5v PSU to 12v ? I understand the ampage of a battery cell has to be capable(I learned this fact from your replys) I'm sorry If you cant read my posts, thankyou for your time.
     
  19. cmartinez

    AAC Fanatic!

    Jan 17, 2007
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    Stepping up the voltage of any DC source (be it a battery or something else) requires a special circuit that may or may not be beyond your expertise. You can always buy an easy to use module for this purpose. But if what you want is to build the circuit yourself, then I think you should know that it's not a project I'd recommend to a beginner in electronics.
     
  20. MarkSimms

    Thread Starter Member

    Apr 6, 2016
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    so a battery cell would not work then?
     
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