Why totem pole output should not be tied together

Discussion in 'General Electronics Chat' started by rainaby, Nov 8, 2011.

  1. rainaby

    Thread Starter New Member

    Nov 6, 2011
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    Can anyone please explain why totempole outputs should not be connected together what is the solution
     
  2. SgtWookie

    Expert

    Jul 17, 2007
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    If you tie two totem-pole outputs together, they will "fight to the death" if they are set to different logic levels.

    You can use diodes from each output with a pull-up or pull-down resistor, depending on the logic you want.

    You can tie open-collector outputs together and use a pull-up resistor to create a wired AND gate.
     
  3. rainaby

    Thread Starter New Member

    Nov 6, 2011
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    i am srry but wats a pull down resistor
     
  4. SgtWookie

    Expert

    Jul 17, 2007
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    1,728
    A pull-down resistor has one end connected to the low voltage in the circuit; in the case of TTL and CMOS, that is usually ground or Vss.

    A pull-up resistor has one end connected to +V, Vcc or Vdd.
     
  5. rainaby

    Thread Starter New Member

    Nov 6, 2011
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    Thnks bro!
     
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