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Ladder diagram to CMOS logic

Discussion in 'Electronic Basics' started by Allen Bong, Oct 27, 2008.

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  1. Allen Bong

    Allen Bong Guest

    Hi group,


    +12v
    |
    NC |
    | |, .-. |
    IN -+--------,-´-------( X )-+
    | ´| | '-' |
    | |
    | | |NO .-----. |
    +---| |--+------| |--+
    | | | | '-----' |
    | | RELAY |
    | T | |
    | --- | |
    +---o o--+ |
    |
    |
    (created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)


    I have the above ladder diagram consisting a relay, a buzzer and a
    push button switch.

    I would like to sound the buzzer "x" when the input is low and when
    the button is pressed the relay would be switched on and holds itself
    through the "NO" contact and the buzzer is switched off due to the
    "NC" contact is opened. Both the NO and NC contacts belong to the
    same relay. When the input goes high, the relay releases and the
    circuit goes back to normal waiting for the next alarm.

    I would like to convert this into a circuit using cmos chips. I use
    an AND and inverters and a 4013 FF and came out with the circuit
    below.


    VCC
    VCC +
    .-. |
    ALARM=L | |10K .-----.
    NORM=H | | | |BUZZER
    '-' '-----'
    IN|\ | _4081 |
    -| >O---+-------| \ __4081 |
    |/ | | | )------| \ ___ |/
    | +--|__/ | )--|___|--| VCC
    | +-----+ +---|__/ 10K |> |+
    | | | | | ===
    | o | | | | /-\
    | PB |=| | | === |
    | o | | | GND |
    | | | | +-------------------+
    | | | | .-----. .-.
    | === | +--|Q S D|-VCC | |
    | GND | | | /| | |10K
    | | |_ <|----O< |---+ '-'
    | | |Q R | \| | |
    | | '-----' | |
    | | | 4013 | ===
    | | | | GND
    +----------|---------|--------------+
    | | H -> L
    | |\ |
    +---| >O--+
    |/
    (created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)

    The C and R at the set input of the 4013 is a power-up set to make the
    Q output high during power on. The PB silences the buzzer until a new
    alarm is detected.


    The circuit seems too complicated and I was cracking my head how to
    simply it. I would also like the 4013 to be toggled by both H to L as
    well as L to H transitions. How should I do it?

    Is there any simpler way to do it? Any help very much appreciated.

    Allen
     
  2. Allen Bong

    Allen Bong Guest

    John,

    Sorry about the duplicated posting. I posted twice on the subject on
    Sunday and they didn't appear on the newsgroup and so I posted again
    on Monday and also didn't appear on the group. They all turned out
    this Wednesday morning.

    Yes I have seen your LTspice posting and I am downloading the LTspice
    software.

    Thanks very much

    Allen
     
  3. JeffM

    JeffM Guest

    Google Groups had what turned into a 72 hour latency
    starting ~2:30pm Saturday.
    They weren't fully sync'd until ~5:30 Tuesday.

    Some people were too clueless
    to notice that Google wasn't doing any updates.
     
  4. Guest

    They (Google) want to do Phone and TV don't they? THAT should be
    special.

    GG
     
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