Discussion in 'Homework Help' started by Guest32, Jan 24, 2012.

1. ### Guest32 Thread Starter New Member

Jan 24, 2012
5
0
Hello, everyone. I am taking an online course in digital electronics, but I am almost completely unfamiliar with the material. I am travelling for work during this time, making it harder for me to keep up!

I have a lab due today and I am unsure how to begin. Unfortunately due to my work this past week, I have not been able to sit down somewhere with a reliable internet connection in order to tackle this one.

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Step 1: Draw the unsimplified logic diagram represented by the following Boolean expression:

Y = (A'D' + B'D'') C

To be clear, there is one long bar over everything in the parentheses, but D has a double bar.

Step 2: Using MultiSim (I am somewhat familiar with this program), connect the circuit drawn in Step 1 using AND gates, NOR gates, and inverters. Connect a logic switch to each input and an LED monitor to the output.

Step 3: Construct the truth table of the circuit in Step 2 by setting the input switches to all possible input combinations and noting the output value for each combination. Write down the truth table.

Step 4: Write the SOP (sum of products) expression derived from the truth table. Use Boolean algebra to simplify the expression as much as possible.

Step 5: Draw the simplified circuit from Step 4. Connect using only triple 3 input NAND gates and inverters.

Step 6: Take the truth table from the circuit in Step 5. Verify that it is the same as the table from Step 3.
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So that's my lab assignment. I'm not asking for a complete answer, I know I should learn everything I can on my own, but I would GREATLY appreciate it if someone could steer me in the right direction. If you could do Step 1 and explain, then give me advice for the rest, that would be awesome.

Look forward to hearing from someone! Thank you!

2. ### crutschow Expert

Mar 14, 2008
13,518
3,386
Some basics:
AB is a two input AND gate
(AB)' is a two input NAND gate
A+B is a two input OR gate
(A+B)' is a two input NOR gate

Hope that gets you started.

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3. ### Georacer Moderator

Nov 25, 2009
5,151
1,266
When you get to the multisim part, use a SPST switch (open-closed) connected to Vcc, for ease of use. While not realistic, a short circuit between Vcc and a gate pin will give a HIGH input, while an open circuit will yield a LOW input.

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