Suggestion for a Transformer

Discussion in 'General Electronics Chat' started by akj375, Feb 24, 2012.

  1. akj375

    Thread Starter New Member

    Dec 21, 2011
    10
    0
    Hi All,

    I'm trying to find a 1.2 VA 120Vrms to 5Vrms transformer. I've found one on mouser.com - part no. 546-161FA10. However, I'm prohibited by two things, the price and the sized. This particular one is $6.12 and I'm a student and need to buy a few of them for a project. I'm wondering if anyone can recommend something with similar specs but cheaper and possibly a bit smaller in size (or at least not any bigger but cheaper). Any suggestion would be greatly appreciated. Thank you!
     
  2. K7GUH

    Member

    Jan 28, 2011
    191
    23
    Unless you absolutely must have a transformer for the project, check out the wall warts at any supplier. They should be a dime a dozen at Goodwill.
     
  3. akj375

    Thread Starter New Member

    Dec 21, 2011
    10
    0
    Honestly my problem is that I just want to build a specific power supply that's as small as possible, but puts out a voltage of 5.5v or so and upwards of 200mA power, but is small. Like as small as some of the usb wall chargers some of which are as small as 1.5"x2"x1.5". I'm having trouble doing this because power supplies with transformers are huge. How do they make those small ones sooo small?
     
  4. #12

    Expert

    Nov 30, 2010
    16,298
    6,810
    Switching regulators.
     
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  5. akj375

    Thread Starter New Member

    Dec 21, 2011
    10
    0
    Do you have any reference where I can read more about constructing such a supply? Thanks in advance.
     
  6. wb2vsj

    New Member

    Feb 19, 2012
    7
    0
    Does it heave to be exactly 5.5V? USB power supplies (like for charging your cell phone) are 5V. You can get 6V "wall wart" supplies as someone suggested quite easily. 5.5V is going to be tricky. I'll try and find some links to cheap suppliers.

    Edit - If you can live with 5V, go to eBay and search for 5V power supply. There are some there for under $4 with free shipping from Hong Kong - "Caveat Emptor"
     
  7. #12

    Expert

    Nov 30, 2010
    16,298
    6,810
    Here are 2 pix of a Nokia 5V 350ma, 120VAC input switching supply next to a US quarter. There is no IC on this board. It's all discrete!
     
  8. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    My local surplus electronics parts distributor buys "surplus" items then sells them.
    They had thousands of new 5V/2A name-brand tiny switching regulated power supplies for $1.75 each. I bought a few. They have a trimpot inside to adjust the regulated output voltage over a wide voltage range.
     
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