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Help with inverter

Discussion in 'General Electronics Discussion' started by Youngfella, Feb 2, 2013.

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  1. Youngfella

    Youngfella

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    Feb 1, 2013
    Pls can anyone help me design a chipless inverter,what i intend to do is to convert dc to ac with an inverter then connect it to a transformer bcos i heard transformer works with ac only,then i will step up the voltage
     
  2. duke37

    duke37

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    Jan 9, 2011
    You will need to give much more information.

    1. What is the DC source?
    2. How much power?
    3. Output AC or DC?
    4. If AC, what frequency and waveform?
    5. What output voltage?
    6. Does it need to be stabilised?
    7. What is wrong with a chip?
    8. Do you need isolation between input to output?
    9. Is there a size restriction?
     
  3. Youngfella

    Youngfella

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    Feb 1, 2013
    Its 5v dc

    1:-Its 5v dc And i will like to invert it and covert it to ac(any waveform as long as its ac),and step it up to 12v dc using a transformer.
    2:-why i want it chipless its bcos the country and state that i live in has no radioshack,its underdeveloped,and i can have access to any chip.
     
  4. davenn

    davenn Moderator

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    you answered the first and third questions :)
    now answer the other 7, so people can help you

    you do realise that transformers dont work with DC ?

    Dave
     
  5. davenn

    davenn Moderator

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    have you googled DC to AC inverters ?
    there are many circuits online, choose one and modify to your needs
    then you will need to rectify it back to DC

    this is all so very power inefficient, where a simple DC - DC boost converter is so easy to do with 1 chip

    anyway ... as I said ... answer all the other questions

    Dave
     
    Last edited: Feb 4, 2013
  6. duke37

    duke37

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    Yes, please answer the questions.

    I have just made a 12V DC to 300V DC convertor using a pair of fet transistors and a home made transformer on a TV line output transformer core. I used 1 turn/volt and used old wire from TV scan coils. I get 20W out at an efficiency of 80%.

    Fets may not be suitable for a self oscillating circuit (I used a chip to drive mine) so you may need to go to junction transistors in an old style, less efficient, circuit.

    The power you want will determine the circuit and devices to be used.
     
  7. Youngfella

    Youngfella

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    Feb 1, 2013
    Hey

    i dont understand u dave,"didnt u see i wrote i want to invert d dc to ac(using an modified inverter circuit,not inverter chip) bcos i know transformers work only ony ac not dc"bcos a transformer produces a magnetic induction only when an alternative current passes through it,u said i should answer d remaining 7 questions,and again u wrote a different thing under it,and why quoting someone to me
     
    Last edited: Feb 4, 2013
  8. Youngfella

    Youngfella

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    Feb 1, 2013
    Q1-anwsered
    Q2-any
    Q3-final out should be dc.
    Q4-sine wave of maybe 30-40hz
    Q5-answered
    Q6-yes
    Q7-answered
    Q8,no
    Q9-no
     
    Last edited: Feb 4, 2013
  9. davenn

    davenn Moderator

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    "any" is not a workable answer for Q2

    we need to know specifics, else we cannot recommend a suitable circuit
    so what sort of things do you want to power from this inverter ?

    what is the source of your 5VDC going to be ?
    we need to know its current capabilities

    Dave
     
  10. davenn

    davenn Moderator

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    because you are NOT giving us ALL the information so that we can help you

    did you do as I asked and google DC tro AC inverters ?

    Dave
     
  11. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    Also, if the answer to Q3 is "DC", then your answer for Q4 contradicts it.
     
  12. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    Nov 28, 2011
    Youngfella. This thread is going round in circles. It's up to 11 posts already and we still know very little about what you want to do.

    If you want to see some useful answers, you need to start by DESCRIBING your WHOLE PROJECT.

    WHAT is the PURPOSE of the project? What are you going to use to POWER the inverter? What are you going to connect to the OUTPUT of the inverter?

    Tell us as much as you can about the whole project.
     
  13. Youngfella

    Youngfella

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    Feb 1, 2013
    Listen i already googled it b4 i even opened this thread but the circuits i see am not sure if they will work,and i dont want to waste my time on them,"actually what i wanted to do was to power my ide harddisk from a usb(5v dc),u know a harddisk requires a dc volt of 5v and 12v,ive seen voltage doublers online but i dont trust the some have their capacitor fixed in some way i dont understand,hw can i build a circuit i dont understand so an thinking d only way is to make an inverter circuit,but i will apprecite any help based on voltage doublers,inverter etc as long as its chipless and can power d harddisk.
     
  14. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    You can't draw enough power to power a hard disk from a USB port. A standard USB2 port supports up to 5 standard loads of 100 mA each, so the limit is 500 mA maximum, which is 2.5W (P=VI); a typical 3.5" hard disk requires 0.7A at 5V (3.5W) and 0.5A at 12V (6W) so you need 9.5W input power, and that's not even factoring in power supply efficiency.

    You would need at least 12W input power, and a standard USB load is 2.5W maximum. Unless you can come up with an overunity device, you can't do it.

    If you had included this basic information in your first post, you would have received an immediate answer and you would have avoided wasting the time of three important contributors on this forum: duke37, davenn and (*steve*).

    There ARE hard disks that can be powered from a USB port. They are specially designed low-power hard disks with a reduced rotation speed, carefully designed to draw minimal power. You cannot power a standard hard drive from a standard USB port.

    http://en.wikipedia.org/wiki/Universal_Serial_Bus#Power
     
  15. davenn

    davenn Moderator

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    Sep 5, 2009
    Thanks Kris

    hopefully that clears it up for him :)
    yeah for a standard hard drive that runs off 5V and 12V it just aint gonna happen
    the power losses through an inverter would be very high
    Even with the much more efficient IC based boost converter it wouldnt have happened anyway, still not enough input current capability from the USB port


    Yup and they only require 5V. Not 5V and 12V :)

    Dave
     
  16. Youngfella

    Youngfella

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    Feb 1, 2013
    Last edited by a moderator: Feb 5, 2013
  17. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

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    Nov 28, 2011
    I've watched the videos. They show that it's possible to convert a DC voltage to a higher DC or AC voltage. This method is used in battery-powered inverters and uninterruptible power supplies.

    You need to learn some basic physics. Start by learning about voltage, current, resistance, and power, and how they are related. Google can help you here. Read my post #14 on this thread carefully and notice the units I have used. Voltage, current, and power (measured in watts).

    I'm not going to spoon feed you a more basic explanation here because you will benefit a lot more from learning all about these quantities, not just how they relate to your specific case.
     
  18. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Youngfella, in Australia we have a word for people like you. 6 letters, starts with DR and ends in ONGO.

    It doesn't matter how many times you post links to videos showing DC-DC converters, you have failed to recognise the actual problem.

    The problem is... There is simply insufficient power available from USB to provide the peak power required for a 3 1/2 inch drive. In fact it is sometimes insufficient to power a 2 1/2 inch drive (which is why they have those adapters that plug into 2 ports). In your case, you would probably have to plug in to 4 or more ports to get the power you require.

    If you reply to my post with those youtube videos, I will not be a happy moderator.
     
  19. davenn

    davenn Moderator

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    Im already an unhappy moderator ;)

    Dave
     
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