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4P2T switch -what's available

Discussion in 'Electronic Components' started by [email protected], Feb 10, 2007.

  1. Guest

    I need a 4 pole double throw switch, but all I can find are toggle
    switches like this:
    http://www.maplin.co.uk/Module.aspx?TabID=1&ModuleNo=2343&doy=10m2

    What other types of switches of this type (4P2T) are available, and
    where?
    I'd prefer something like a PCB solderable slide-switch in a vertical
    position, but I'll consider anything smart and modern looking.
     
  2. Eeyore

    Eeyore Guest

    4 pole switches aren't very common. What load current and voltage are you
    switching ?

    Graham
     
  3. Guest

    It's just for video signals. I don't know the voltage/currents, but
    I'm pretty sure it can't be more than 12V and a few mA. Any low
    voltage switch should do.
     
  4. Maybe a pair of DG111 analog switches?
    http://www.maxim-ic.com/quick_view2.cfm/qv_pk/1315

    I'm not sure how well they cope with video signal rates, but if you use
    individual switches to form SPDT pairs, two IC's will be enough, and you
    can control it with any SPDT toggle switch you like. You can get your
    alternating control levels directly from a physical toggle switch.
     
  5. Meant DG211...
     
  6. Eeyore

    Eeyore Guest

    Does it have to be a physical switch 4 pole ? How about a single pole switch of
    your choice and some relays ?

    Do you mean actual video or RF btw ?

    Graham
     
  7. Eeyore

    Eeyore Guest

    The channel resistance may be a bit high actually or I'd have suggested that
    too. You could use discrete fets though.

    Graham
     
  8. Guest

    All of this sounds very good except I wouldn't know where to start :-(

    My electronics knowledge restricts itself mainly to creating working
    circuits out of schematics and other practical things. Not designing
    stuff from scratch.

    The circuit I'm working on in Eagle for creating a complete PCB is the
    following diagram I found somewhere:
    http://img236.imageshack.us/img236/2712/stmsyncvganl4.gif

    It allows for a standard PC (VGA) monitor to be connected to an Atari
    ST as opposed to just the special Atari monitor itself.

    If the VGA monitor is a multisync type (e.g. it can handle all of the
    Atari ST frequencies (*)) the switch can be used to choose colour or
    mono modes.

    (*)
    Atari ST monochrome mode:
    35.70 KHz horizontal
    71.2 Hz vertical

    Atari ST colour mode:
    15.75 KHz horizontal
    50/60 Hz vertical
     
  9. Have a look at the DG211. Looks like you might be ok with two of those.
    Eeyore mentioned that the on resistance might be a bit high, but as you're
    using a circuit that uses 62 ohm resistors in three of the four lines, it
    won't matter there. The 'monochrome sensor' line is probably a DC level
    state line, so it won't matter there either.

    If you can handle soldering and veroboard, you'll not have much trouble.
    Just check VERY carefully before connecting to the computer's 5V supply.
    The Analog switch IC's are very easy to use. The most awkward bit will just
    be working out how you will route the connections.
     
  10. Just realised, you might need a 12V supply. That Atari plug appears to
    provide one, which is helpful. The DG211 can work with 22V in some
    versions, 12V should be safe for all.
     
  11. Your VGA monitor can go down to 16 kHz horizontal sync ? Which
    model is it ? I've never seen any that went below about 30 kHz.
     
  12. Guest

    Not a VGA monitor.
    I was referring to Multisync monitors. I used to have an NEC Multisync
    II which could handle all of the Atari ST's sync rates.
     
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