Logical Gates

[lingz89]

Hi, I'm struggling with the topic of logical gates so I hope someone can help me out.
I'm having trouble with the following:
- boolean expressions, De Morgan Law and expressing terms in NOR/NAND only.
- designing circuits
- implementing circuits with given inputs/outputs (4 bit adder?)

An example of the question I'm struggling on would be:

'Write boolean expressions and design a ciruit with three inputs and one output such that the output is 1 if and only if two or more inpurs are 1.'

Help appreciated, I'm finding this topic so confusing.

[angryboy]

little sample:

public static boolean andGate(boolean in1, boolean in2){
  if(in1 && in2) 
    return true;
  return false;
}

public static boolean orGate(boolean in1, boolean in2){
  if(in1 || in2) 
    return true;
  return false;
}

the int version would be:

public static int andGate(int in1, int in2){
  if(in1==1 && in2==1) 
    return 1;
  return 0;
}

public static int orGate(int in1, int in2){
  if(in1==1 || in2==1) 
    return 1;
  return 0;
}

Now you would do something similar for NOR/NAND using three inputs.
check out wikipedia for the truth table, it'll help you out.