NC Switch IC

Discussion in 'General Electronics Chat' started by shivaaa, Jan 5, 2011.

  1. shivaaa

    Thread Starter Member

    Jan 5, 2011
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    Hi, Can anybody tell me is there Any IC switch which is closed normally and if we give input control which opens the Switch

    Ex: CD 4066 Quad Bilaterl Switch, which is open Normally and if control voltage given it will close. I want opposite of this
     
  2. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    Maybe a little more about your application? There are photomos DC solid state relays in IC packages that are form-B (NC).

    Ken
     
  3. shivaaa

    Thread Starter Member

    Jan 5, 2011
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    Thanks for the Response..

    I just wanted to feed a 12VDC to a Relay which will drive an AC Motor of 230VAC. But before the 12VDC Relay I want to use 3 types of Relays ( 2 NC and 1 NO) which are independent and Which will feed the 12VDC Relay.

    so my question is intead of those relays can i use any IC which has a control input and the control High should make the contact open circuit.?

    As you mentioned, the solid state relay IC? Can you give me more information about that?

    Thanks again..
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
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    An important parameter is the motor current. What is the maximum current rating?
     
  5. shivaaa

    Thread Starter Member

    Jan 5, 2011
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    Motor current may be 2 or 3 amps. but here we need not worry about motor current becuase the 12VDC Relay is sufficient to handle that.

    The thing is I have some relays before 12VDC relay. I want to replace those Relays with some ICs.

    Say, I have two relays A and B.

    The Relay B handles the Motor. Which is normally open.

    Relay A will handle only the DC voltages. Which is normally closed. Depends upon the Input to the Relay A, it will Open or Close the Relay B which is connected to motor.

    Now I want to Replace the Relay A with some IC.
     
  6. retched

    AAC Fanatic!

    Dec 5, 2009
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    Like a MOSFET?
     
  7. shivaaa

    Thread Starter Member

    Jan 5, 2011
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    Thanks first

    ..MOSFET is also fine for me. I have not used MOSFET yet. If MOSFET can plays like a NC and NO Relays it wil be fine.. Can you give me some ideas....
     
  8. retched

    AAC Fanatic!

    Dec 5, 2009
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  9. shivaaa

    Thread Starter Member

    Jan 5, 2011
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    Thanks for the reply. let me try this and let u know
     
  10. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    If the other relays are not switching any large amount of current (<20mA), it sounds like CMOS Logic ICs might be the solution to your problem. It would appear you are trying to add "gates", at a guess, to decide if the AC motor should be on or not.

    If the other relays are controlling AC loads, then ignore this. :)
     
  11. shivaaa

    Thread Starter Member

    Jan 5, 2011
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    I have attached a circuit diagram conrolling Motor, using 6V Relays, The problem is in point A and B, am able to supply one about 2 to 3 V which is not sufficient to make the Relays energize...

    Anybody can think of anything? I tried using different combinations of NPN Transistors as Darlington.. still not able to find..
     
    Last edited: Jan 13, 2011
  12. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    What are the requirements to turn on the AC relay, both A and B are +V?

    If so, a CMOS AND gate will do this, and possibly drive the relay coil through a transitor (in which case, a NAND gate would give the correct polarity).
     
  13. shivaaa

    Thread Starter Member

    Jan 5, 2011
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    Conditions are:
    If

    A = 1 , B=1 , AC Relay OFF (which is normally Open)
    A=0, B=1, AC Relay OFF
    A=0 , B=0, AC Relay ON(Which will Turn On the Motor)
    ----------------------------------------------------
    Now,
    A=0 , B=1, AC Relay should be ON (Motor should be running still)
    A=1, B=1, AC Relay is OFF, Motor Off
     
  14. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    Ok, so there are two inputs, A and B
    Two outputs, Motor and Relay

    I only see the relay in the drawing above, with the motor connected to it, or is the AC relay the box on the B line?
     
  15. shivaaa

    Thread Starter Member

    Jan 5, 2011
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    N.O is the AC Relay, Other 2 NCs are just operating in DC, for your referece i redraw the diagram with name for the relays...
     
  16. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    So the AC Relay should be on (and thus the motor)
    WHEN:
    A and B are False OR A is false, and B is TRUE.
    All other conditions, The Relay (motor) will be OFF.

    Is this correct?
     
  17. shivaaa

    Thread Starter Member

    Jan 5, 2011
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    So the AC Relay should be on (and thus the motor)
    WHEN:
    A and B are False OR A is false, and B is TRUE.
    All other conditions, The Relay (motor) will be OFF.

    One More Condition, see in line 2. ( A=0, B=1, AC Relay OFF ).

    I need the conditions exactly one by one which i listed earlier.
     
  18. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    Isn't that what I posted?

    Relay/Motor I'm thinking are the same thing, are they not?
     
  19. shivaaa

    Thread Starter Member

    Jan 5, 2011
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    from my Image, R-AC is the Relay operating the motor.

    you can see two different conditions in my post,
    ----------------------------------------------------------
    initial conditions are,

    1. A = 1 , B=1 , AC Relay OFF (Motor Off)
    2. A=0, B=1, AC Relay OFF(Motor Off)
    3. A=0 , B=0, AC Relay ON(Which will Turn On the Motor)

    ----------------------------------------------------
    Once the Motor is ON and running Now the condition shuld be,

    1. A=0 , B=0, AC Relay ON(Motor ON)
    2. A=0 , B=1, AC Relay should be ON (Motor should be running still)
    3. A=1, B=1, AC Relay is OFF, Motor Off

    Check the Line 2 in two conditions, both are different.
     
  20. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    My question is, what line is running the motor? The boxes don't match up, I only see one motor, connected to the AC Relay for power. :confused:
     
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