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DC Power Jacks

Discussion in 'General Electronics Discussion' started by Anfield, Jul 20, 2013.

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  1. Anfield

    Anfield

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    0
    Jul 20, 2013
    Hi:
    I'm trying to assemble a hub to provide power and USB connections to accessories on my telescope mount. The idea is to reduce cable clutter by having one USB cable from the PC to the hub and one power cable running from the 12V DC battery to the hub. I intend to mount power jacks on the hub (an aluminum box) and change the power connectors on the accessories (DSLR camera, focuser motor, CCD camera, telescope mount) to enable connections to these jacks. The typical DC power jacks available at Radio Shack seem to maintain a seemingly weak coupling and I wondered if I could use RCA jacks instead. I know they are meant to carry audio signals but would they be able to carry 12V and up to 5A? Any help and advice would be greatly appreciated. Any alternatives to the DC jacks would be welcome too.
    Thanks.
     
  2. davenn

    davenn Moderator

    13,674
    1,892
    Sep 5, 2009
    Hi
    welcome to the forums :)

    RCA's at 5A may be pushing it a bit ... personally I wouldnt put more than maybe 2 - 3 Amps through them

    there's a huge range of 2 and greater pin connectors available that can easily handle 5Amps
    I dont know what country you are in ... its always good to fill in that info in your profile
    have a look on digi-key, farnell, for 2 pin DC connectors

    Dave
     
  3. shrtrnd

    shrtrnd

    3,773
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    Jan 15, 2010
    I'm not going to research this again, I've posted information repeatedly about the fact that there are SEVERAL sizes of DC power jacks, not just one.
    Pin lengths vary, pin and jack barrel diameters vary. You have to get the right
    physical size plug for your equipment.
    Another issue I've heard, is problems with BNC connectors.
    There are 50 Ohm and 75 ohm BNC connectors, and their pin sizes and socket sizes
    are different. You have to research those before buying mating connectors, so you
    don't wind-up with mis-matched sizes resulting in poor connections.
    BNC outsides look the same, but the pins/socket connections are different.
     
  4. woodchips

    woodchips

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    Feb 8, 2013
    Umm, it is N connectors where the pin sizes change between 50R and 75R, BNC are the same just missing the PTFE around the socket to change the impedance.
     
  5. shrtrnd

    shrtrnd

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    Jan 15, 2010
    There are different pin/socket sizes in BNCs.
    I know, because I've had to correct engineers who wanted connector panels
    built, but specified mis-matched BNC connectors.
    Believe but you will, .... I'm just saying.
     
  6. davenn

    davenn Moderator

    13,674
    1,892
    Sep 5, 2009
    shrtrnd .... not sure how you got onto BNC connectors ?? ;)

    not really designed for DC power anyway

    Woodchips ... as I said earlier.... go to farnell etc and do a search on DC connectors... there's dozens of varieties

    Dave
     
  7. shrtrnd

    shrtrnd

    3,773
    493
    Jan 15, 2010
    davenn, because DC power jacks have different pin and socket sizes too, ....
    Both connectors make unreliable electrical connection, if the wrong sizes are mated.
    I can't tell you how many people I've known who have asked me if I wanted equipment they
    intended to throw away because they thought it was broken, ...only for me to find that
    they were trying to use incorrectly-sized, connectors pin/socket combinations.
     
    Last edited: Jul 23, 2013
  8. woodchips

    woodchips

    43
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    Feb 8, 2013
    At the risk of spoiling the party, manufacturers of BNC connectors say that the 50R and 75R are completely mechanically interchangeable.

    Actually BNC can make good power connectors, cheapest locking type available, also pretty reasonable power handling, and working with circular cable, coax, is sometimes of real use.
     
  9. shrtrnd

    shrtrnd

    3,773
    493
    Jan 15, 2010
    I sometimes wonder why the intelligencia bother asking questions here.
    As I've said before, I often wonder why I wasted 43 years doing this; when I already
    knew everything there was to know about electronics when I was 17.
    Go get 'em, woodchips!
     
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