# Homework Help: Logic Circuits

1. Apr 24, 2015

### DeathDealer

1. The problem statement, all variables and given/known data
https://www.dropbox.com/s/d3qdr96n27j8wa7/circuit.png?dl=0

The questions is as follows: For each circuit write the equivalent logic expression.
2. Relevant equations

(B' + C) * A (?) My Attempt at circuit 2
(A* (A' * C') * B') + (A * C * B) My Attempt at Circuit 1

3. The attempt at a solution

I attempted circuit 2 and circuit 1 but circuit 2 is easier because i think i know some of the basics but circuit 1 was very complicated (I did look at it and try to work it out, my best guess really) and i really need an assist on that as for circuit 2 here is what I got and my reasoning: (B' + C) * A

In the second circuit you have three gates. A "NOT" gate, a "OR" gate and an "AND" gate.

1) "NOT" gates inverts the input. An input of '1' for a NOT gate would result in a '0' and an input of '0' would result in a '1'. So if the input is say x we denote the output by x′ where x′ denote the opposite of x. So B becomes B'.

2) "OR" gates take two inputs and add then together. Basically this means if the two inputs are x and y the output will be x+y. So B' becomes B'+C

3) "AND" gates take two inputs and multiplies then together. Hence if the two inputs are x and y the output will be xy. So B' + C becomes (B'+C) * A

Last edited: Apr 25, 2015
2. Apr 25, 2015

### axmls

Yes, that is correct. Have you made an attempt for circuit 1?

3. Apr 25, 2015

### DeathDealer

I found it very hard. I know what the gates mean but all those pathways going everywhere is just to confusing. BUT if i had to guess I would say something like: (A* (A' * C') * B') + (A * C * B).

Last edited: Apr 25, 2015
4. Apr 25, 2015

### axmls

Just start from the right side, and work backwards slowly. Take your time.

5. Apr 25, 2015

### DeathDealer

Am I close? (A* (A' * C ') * B ') + (A * C * B)

6. Apr 25, 2015

### DeathDealer

I also came up with some tables is this right?

#### Attached Files:

File size:
4.5 KB
Views:
117
• ###### 1.gif
File size:
3.7 KB
Views:
111
7. Apr 25, 2015

### DeathDealer

I think i mucked up circuit 1: its (A* (A' * C ')' * B ') + (A * C * B). Could someone tell me if i'm right?

#### Attached Files:

• ###### 2.5.gif
File size:
4.5 KB
Views:
108
8. Apr 25, 2015

### axmls

Yes, that looks correct.