# Desperate NEED OF HELP series-parallel circuits

#### iceman_blazin

Joined Oct 21, 2007
6
o-------------------------------o
-......................-.....................-
-......................-.....................-
-...............R1 200ohm.........R3 150 ohm
-.....................-......................-
60v...................-....................-
-.......................-....................-
- ....................... - ................. -
- .........................-........................-
-................R2 100 ohm .........R4 350 ohm
- ......................-.......................-
- .......................- .........................-
-........................-........................ -
o-------------------------------------o
Hey, i am trying to find the (EIR) like the chart version and i have no clue on how to solve this problem i missed the day he went over it and now i am stuck and just need help so if you can show me how to solve this that would be great thank you in advance
- = flow of current
. = so the picture will come out fine

#### Dave

Joined Nov 17, 2003
6,969
It might help if you could scan in and upload your circuit because I like many probably cannot decipher your OP drawing.

Is it supposed to be a 60V source with R1 in series with R3, R2 in series with R4, and both these two series arrangements in parallel with each other?

Dave

#### Management

Joined Sep 18, 2007
306
I think that since '-' is the flow of current that the battery is in parallel with both the series connections R1 - R2 and R3 - R4. This might have went over my head but what is EIR? I know Equivalent Resistance but what is I ... current?

#### iceman_blazin

Joined Oct 21, 2007
6
sorry about that here is a attachment

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#### iceman_blazin

Joined Oct 21, 2007
6
E- volts
I - current
R - Resistance

#### Management

Joined Sep 18, 2007
306
Well do you know Ohms Law of E = IR? Resistors in series and circuit elements in parallel. That battery is in parallel with both sections of resistors. Also, when the the same current runs through two or more resistors they are said to be in series. What can you so with resistors in series? And since the bettery is in parallel, you should be able to figure out the math calculations with Ohm's Law.

#### Dave

Joined Nov 17, 2003
6,969
I don't have Word installed on this PC so can't look at your specific query. Can I point you in the direction of the reference section in the e-book that will be of use:

Deal with the series elements first, then the parallel elements. Also remember:

For components in series, the current through them is the same.

For components in parallel, the voltage across them is the same.

Dave

#### iceman_blazin

Joined Oct 21, 2007
6
yeah i was told to combine the resistors, and i dont know how to do that, like R1+R2 and R3+R4, then to solve for the resistance and then go back with teh resistance and solve for the voltage but i kinda need step by step or i really wouldnt kno whow to do it what program do you have i can do another link

#### iceman_blazin

Joined Oct 21, 2007
6

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#### iceman_blazin

Joined Oct 21, 2007
6
i seen that but one more question, it really doesnt show where or how i combine resistors when they are in a series, do i just add the Ohms together to get a grand total and then when i find the current then plug in to find the volts?

#### Management

Joined Sep 18, 2007
306
Yes you are right in your assumption. When resistors are in series (same current) that can be combined by add their resistances together. Keep in mind you are also adding the individual voltages of each together as well to combine to get the total voltage across them both.

V = IR1 + IR2 = I*(R1+R2)

But like Dave said, components in parallel have the same voltage. This includes sources as well like your 60V battery.