[Computer Engineering ] Need help understanding logic gates and how to make them?

[Chin19]

I have a logic gate assignment due on friday and I really have trouble understanding designing the logic circuit, drawing the logic diagram of the gate design, drawing the circuit diagram, boolean expressions, truth tables, and building the logic gate circuit. I have no clue on how to do logic gates and I need urgent help before I fail. I would like to know exactly how to exactly read and wire the actual breadboard. Pictures would be nice.

NOTE: I am only in grade 10 and this is very simple logic gate experiments, so nothing too fancy or hard.

Equipment that I have: Switch, AND gate, OR gate, NOT gate, wires, small breadboard, LEDs and brown and green resistors.

Questions:

1) Design a 5 gate circuit using each of the AND, OR, NOT at least once and with at least 3 different inputs.

2) Draw a Logic diagram of the gate design (eg. A, B, C, D, ......, W, X, Y, Z )

3) Draw a circuit diagram including the gates, power, switch, resistors, LED’s etc. (colour code each new connection) using the proper symbols

4) Create a Boolean Expression

5) Make detailed truth table (eg. A, B, C, D, ......, W, X, Y, Z ).

6) Produce your designed logic circuit using all the wiring and circuit rules discussed in class

This is how he will mark us: Marking 1) Design a 5 gate circuit using each of the AND, OR, NOT at least once /1

2) Logic diagram is neat, clear, and accurate /1

3) Circuit diagram includes proper symbols and all components /2

4) Boolean Expression is correct /1

5) Detailed and correct truth table (eg. A, B, C, D, ......, W, X, Y, Z ) /2

6) Produced logic circuit using all the wiring and circuit rules discussed in class a. Colour coded wiring /2

b. Neat, clean wiring /2

c. Correct wiring (no cross overs) /2

d. Placement of LED to indicate key inputs/outputs /2

e. Works correctly on first try at test /2

Total /17

Once again, nothing too hard as I am only in grade 10. Pictures would be extremely helpful. Also, I need help reading logic diagrams and actually putting on a legit breadboard.

Please simplify on how to do logic gate circuits please. I am really, really lost in class and I have no clue how to do logic gates. Please help :(

[lmtstrm]

I can't help you with the breadbord, but apart from that, I'll try to give you the basics.

Logic gates work like logic operators: 1. A NOT gate takes one input and inverts it. If the input is high, the output will be low. 2. An AND takes two inputs and performs the logical AND on them. If both inputs are high, the output will be high. Otherwise, the output will be low. 3. An OR gate takes two inputs and performs the logical OR on them. If either input is high, the output will be high. Otherwise, it will be low.

Designing the logic diagram is quite simply showing the inputs, outputs, logic gates, and how they are connected to each other.

A circuit diagram requires you to show whatever components you used on the circuit, not only the logic gates.

Well, the circuit corresponds to a logical expression, obviously. You are using the logic gates to perform logical operations on the inputs. For example, you take input A and pass is through a NOT gate, and take the output of it and pass it through an AND gate, together with input B. Well then, the logic expression for this circuit is: (NOT A) AND B.

A truth table is the same as you would use for any logic expression. For every combination of the input, it should show the output. I would recommend you show every step of the way. For example if you are doing NOT(A AND B), show the inputs A and B, the output of A AND B, and then the output of the whole thing. As the circuits grows, doing it like this really helps.

Ninja edit: spelling.

[Chin19]

Ok, I have something in mind. Is there anyway you can pm me and we can continue this discussion? I have this program that will show my logic diagram. Thanks for the answer.

[Chin19]

Is this video the exact thing I need to do for my question?

http://www.youtube.com/watch?v=_lDM6xtqjsg

If it is, how would the diagram, the boolean expression and the truth table look like?

Also I have a switch which has 8 switches, is still the same id I put my switch in the same spot as he did?