# Combination circuit resistance calculations

#### leekel

Joined Jun 21, 2021
13
Hello all. I am working on a pre-lab for my DC circuits class and this question has me a bit stumped. I have been asked to calculate the following:
• Resistance of BD
• Resistance Total
• Resistance of BC
• Resistance of CD
I understand the series and parallel equations for resistance, but I am struggling with the flow of the current here. would it go in at A, then split at B, coming out at D and ending at E?

How would I find the resistance from B to D? From B to C? and from C to D?

I believe the total resistance would be 1,428.57Ω, with 628.57Ω coming from the middle section, and having 330Ω and 470Ω added to it. This may be incorrect but that is how I would think to do the total resistance.

Thank you in advance for any help that is offered.

#### ericgibbs

Joined Jan 29, 2010
18,219
hi,
Welcome to AAC.
What do you calculate the sum of the 3.3k and the 1.2k to be.??
E

• leekel

#### leekel

Joined Jun 21, 2021
13
hi,
Welcome to AAC.
What do you calculate the sum of the 3.3k and the 1.2k to be.??
E
I would think it to be 880, since it is a part of the parallel, but I may be confusing myself and it may just be 4.5k

#### ericgibbs

Joined Jan 29, 2010
18,219
hi,
Your over complicating it.. What do you calculate the Series sum of the 3.3k and the 1.2k to be.??

E

Hint: forget about the 330R and the 470R and the 2k2 for now..

#### leekel

Joined Jun 21, 2021
13
hi,
Your over complicating it.. What do you calculate the Series sum of the 3.3k and the 1.2k to be.??

E
4.5k

#### ericgibbs

Joined Jan 29, 2010
18,219

#### leekel

Joined Jun 21, 2021
13
hi,
OK,
So your circuit is now, so BD resistance is easy to Read

So also what is the total resistance from A to E..?
E
View attachment 241838
oh wow I did not realize that's how it worked. total would be 2.28k

#### ericgibbs

Joined Jan 29, 2010
18,219
So if A to E is 2.28K what do make the BD value.??

E

#### leekel

Joined Jun 21, 2021
13
So if A to E is 2.28K what do make the BD value.??

E
1.48k I believe ?

#### ericgibbs

Joined Jan 29, 2010
18,219
hi,
Believing is not enough... are you confident.??

What is BD
What is AE.
then we can move on to the BC and CD..
E

#### leekel

Joined Jun 21, 2021
13
hi,
Believing is not enough... are you confident.??

What is BD
What is AE.
then we can move on to the BC and CD..
E
BD - 1.48k
AE - 2.28k

#### leekel

Joined Jun 21, 2021
13 OK, look at this breakdown of your circuit for doing BC

One resistor is in parallel with two resistors in series,

How would you solve this for BC,??

E
View attachment 241840
I would want to combine 2.2k and 1.2k, but do those get solved as a series or a parallel?

#### ericgibbs

Joined Jan 29, 2010
18,219

#### ericgibbs

Joined Jan 29, 2010
18,219
So the 3k3 and the 3k4 are in parallel, so whats the value of BC.??