# DC Series/Parallel Circuit

#### aslaton

Joined Jul 8, 2005
2
Hi,

I'm having a problem with DC Series/Parallel Circuits. I have attachted two schematics named problem 1 and problem 2. Problem 1 asked what is the current flowing across R3 in this circuit? Problem 2 asked what is the power consumed by R2 in this circuit. I have looked and looked at these schematics I just can't figure out how they came up with the answers. Can anyone please help.

Problem 1
[attachmentid=774]

Problem 2
[attachmentid=775]

aslaton

#### Brandon

Joined Dec 14, 2004
306
Originally posted by aslaton@Jul 8 2005, 01:56 PM
Hi,

I'm having a problem with DC Series/Parallel Circuits. I have attachted two schematics named problem 1 and problem 2. Problem 1 asked what is the current flowing across R3 in this circuit? Problem 2 asked what is the power consumed by R2 in this circuit. I have looked and looked at these schematics I just can't figure out how they came up with the answers. Can anyone please help.
Problem 1
[attachmentid=774]

Problem 2
[attachmentid=775]

aslaton
[post=8993]Quoted post[/post]​
These are not that diffucult. You just need to make your KVL and KCL equasions for the circuits as you will need to do for every circuit just about.

Start at the source and do voltage drops around the loop. Vdrop = I*R. All the voltage drops added up should equal the source provided. Then, anyline wire in the same series line always possess the same current. Thats why we have I2+I3=It. Its like a pipe w/ water. If 5 gallons flows per minute in it, no matter how many holes or additional lines you pull off of it, if you measure all the outputs, you will get 5 gallons a minute, same with current.

For I3

48v=It*R1 + (R2||R3) * (I2+I3) + It*R4 KVL
I2+I3=It=1 Amp KCL
R2*I2=R3*I3

For P2

48v=It*R1+(R2||R3) * (I2+I3) + It*R4 KVL
I2+I3=It=1 Amp KCL
P2=I2 * I2 * R2

Just plug n solve