Switch open and close three-way node?

Discussion in 'General Electronics Chat' started by jp1390, Aug 25, 2011.

  1. jp1390

    Thread Starter Member

    Aug 22, 2011
    45
    2
    Hello, just another quick question. I have two 6 V coin cell batteries separated by a ground connection to provide a +/- 6 V supply bias for my circuit. I am wondering if there is a single switch that I can buy to cut off all three connections to cut off?

    VDD-----|i|i|i|i|i------GND------|i|i|i|i|i-----VSS

    I know that I can use two switches both in between each battery and GND but that is a hassel and it puts my system under stress of being powered by only one source.

    Any ideas?

    Thank you!
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Don't worry about disconnecting ground. A double-pole single-throw switch will allow you to connect/disconnect both the + and - supply.
     
  3. jp1390

    Thread Starter Member

    Aug 22, 2011
    45
    2
    Hrm, I understand what you are saying, but I am not familiar with DPST switches. Don't they control two power lines?

    This is my Eagle schematic:

    [​IMG]

    I just don't know where to put the switch? Also, I custom-made the library for these supplies (6V coin cell, 23mm), and I am noticing that the nets don't attach quite onto the ends of their pins and the .brd file doesn't show any connections to these pins. Is there an easy fix for that?

    Sorry for the question bombardment, noob here :/

    Cheers!
     
  4. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Did you snap the pin ends to the grid? That's probably why your wires won't attach.

    DPST switches are like a pair of SPST switches in one package. You might be familar with DPDT switches; double-pole double-throw.

    Here is a thru-hole DPST switch:
    http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=CKN1814-ND

    You can also use a DPDT switch like this one:
    http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=SW619-ND
    You'll probably find much more variety available in DPDT. Just use the two center terminals and one pair of end terminals.
     
    jp1390 likes this.
  5. jp1390

    Thread Starter Member

    Aug 22, 2011
    45
    2
    Awesome I picked up a DPST, thank you for your help!
     
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