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Logic Gates

  1. Oct 19, 2004 #1
    Can someone give me an example of where the following types of gates should be of practical use?

  2. jcsd
  3. Oct 20, 2004 #2


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    Ok, the automatic doors at a supermarket, the idea is to use two sets of doors to minimize the amount of air that can transfer in/out to minimize heating/cooling costs.

    If one door is open then you do NOT want the other door to automatically open.

    If one door OR the other door is open turn on the lights promo music in the space between the doors.

    If one door AND the other door is open turn on the blower fan to keep the air moving in the desired direction and heat/cool it appropriately.

    That help?

  4. Oct 23, 2004 #3
    not: lets say, you have a float in your basement that is nc (normally closed, like a light switch turned on, when not under water). you want to use this float for an alarm. if you wire this float directly to the alarm panel it will be on when the basement is dry! therefore we reverse the incoming signal to the alarm panel through a not gate. consequently; 0=1, and 1=0, so the alarm will only sound when your feet are wet.
    or: lets say, you have a large basement with two water infiltration areas, and also two float switches wired no (normally open, like a light switch off when dry). we really don't care which area has water when we are asleep, we just want to know that there is a problem. therefore; we require an alarm whether float # 1 OR float # 2 is under water, and consequently apply these float signals to an OR gate for an alarm.(0 with 0 input=0 output feet dry/no alarm, 0 with 1 input=1 output, feet wet/ alarm, 1 with 0 input= 1 output, feet wet alarm.
    and; lets say your dog runs away through two doors every time they are both open at the same time.
    we will place a no switch on each door, so that an alarm will sound every time both doors are open, using an AND gate. [0 with 1 input = 0 dog ok & no alarm, 1 with 0 input = 0 dog ok & no alarm, 1 with 1 input = 1 dog may be run over & alarms go off like gang busters (whatever that is) so you to save him/her from peril]
    Last edited: Oct 23, 2004
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