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Correct name for push button switch

Discussion in 'General Electronics Discussion' started by Tyler Monk, Feb 27, 2017.

  1. Tyler Monk

    Tyler Monk

    5
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    Feb 27, 2017
    Hi,
    I am struggling to find the name of the switch I require, and it may not even exsist, hopefully you guys can help.
    I'm looking for a momentary switch that completes on circuit when released and other one when pressed.
    Hope you can help

    Cheers
    Tyler
     
  2. donkey

    donkey

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    56
    Feb 26, 2011
    momentary double pole double throw?
    momentary single pole double throw?
    momentary defines that you have to hold down the button to complete A connection
    double pole/ single pole is how many circuits you can have
    double throw means it connects to 1 device then other. triple throw would connect to 3 items

    the only thing I would say is make sure there isn't an off

    https://www.jaycar.com.au/dpdt-quality-pushbutton/p/SP0714 dpdt
    https://www.jaycar.com.au/sub-mini-pushbut-spdt-mom-hori-r-a-pcb-s/p/SP0380 spdt
     
  3. Bluejets

    Bluejets

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    719
    Oct 5, 2014
    I think the OP is looking for a normally closed push button.
     
  4. Tyler Monk

    Tyler Monk

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    Feb 27, 2017
    Hi guys, thanks for your effort in finding the switch I require. However I still cannot find the one I need. I have two circuits and this switch has to cater to them both. Here is what I'd like it to accomplish

    Be momentary, no latching

    While the button in in its resting position circuit A is closed and connected, and circuit B is disconnected.

    When the button is pressed circuit A is disconnected, and circuit B is then connected

    Hope this is clear, I'm finding it difficult to understand myself to be honest.
     
  5. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

    4,960
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    May 8, 2012
    You're describing a DPDT (PB) switch. Like this.....

    Chris
    upload_2017-3-21_20-53-31.png
     
  6. donkey

    donkey

    1,286
    56
    Feb 26, 2011
    A double pole double throw or dpdt momentary will do the same when wired correctly
     
  7. 73's de Edd

    73's de Edd

    2,744
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    Aug 21, 2015
    Sir Tyler Monk . . . . . . . .

    Lets now compare and evaluate and see egg-zackly what switch action you need.
    From what can I perceive from your initial given information of :

    Be momentary, no latching

    That is where the spring loaded comes into play . . . . it only engages . . . for however short or long of time that you push and hold in the button.

    While the button in in its resting position circuit A is closed and connected, and circuit B is disconnected.

    In the provided graphics the A circuit function normally has a short between 2 and 3 terminals , while B circuit has an open connection. This fullfills the above circuit conditions . . . .when untouched.

    When the button is pressed circuit A is disconnected, and circuit B is then connected

    This is done by the item 8 pushbutton end pressing in pin 12 which starts compressing 11 spring and the pin 12 other end starts its entry into a slightly off centered divot on a pivoting cantilever as GREEN 7, it starts moving CW and moves a spring loaded ball bearing 5 incrementally towards the RED dot position. As the bearing passes the red dot, it has passed a balance point and the spring loaded bearing shortly flips the switch contact to short between 1 and 2 terminals while disconnecting from prior 3 terminal. The ball bearing is now left resting in a like position on the other side of the RED dot.
    Exploded view . . . . au . . . . . Switch Electro-Mechano Action . . . . .

    [​IMG]


    Hope this is clear, I'm finding it difficult to understand myself to be honest.

    Me too !

    This was accomplished with the PINK REFERENCED SPDT switch IF a common wire can be shared.
    If you need a single wire connection to be made and broken at A circuit and the same at B circuit but with NO sharing of wires you would use the drawn BLUE REFERENCED DPDT configuration where you have two wires coming in to pins 3 and 2 of A for a short between those two wires.
    You then use another two wires coming in to B prime pins 1 and 2 where you would have an open circuit until you push the switch

    NOW if you did not need that self choice time of auto returning push switch, you would need what is called a push-push switch where its two switched states alternate each time you fully press in on the switch and then release it.
    Also not given was the power and voltage reqirements needed to be switched.
    Also any physical size limitations.

    What say you . . . . . .

    http://i.imgur.com/KK1xmPc.png


    73s de Edd
     
    Last edited by a moderator: Mar 25, 2017
  8. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    Switches with one normally open set of contacted and one normally closed set of contacted are common in E-stop buttons (although these normally latch)

    I'm sure I've seen non latching switches of this nature...

    Here is a page of them from Digikey. They're described as "DPST (1 NO, 1 NC)"
     
    Last edited: Mar 22, 2017
  9. BobK

    BobK

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    Pricey little buggers, aren't they?

    Bob
     
  10. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    Probably much cheaper to purchase a DPDT momentary contact switch and just use the contacts you need.
     
  11. Tyler Monk

    Tyler Monk

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    Feb 27, 2017
    Guys...... thanks for all your assistance, got what I need now I got a DPDT switch and used that, works a treat. Thanks again fellas
     
  12. Tyler Monk

    Tyler Monk

    5
    0
    Feb 27, 2017
    You sir, should be a teacher, cheers dude very helpful
     
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