Please help a beginner with a Boolean Algebra Lab...

Thread Starter


Joined Jan 24, 2012
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.


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.

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!


Joined Mar 14, 2008
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.


Joined Nov 25, 2009
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.