# Combination Circuits

Discussion in 'Homework Help' started by dahooligans, Oct 28, 2008.

1. ### dahooligans Thread Starter New Member

Oct 28, 2008
5
0
I was wondering if someone could help me find the values listed to the right here, I'm somewhat familiar with this combination circuit stuff but some of these resistors values are not in here and I know that in a series the current stays the same throughout that series, and parallel the voltage is the same across, so i was wondering if someone could help me find the values below and send me a completed image link I would greatly appreciate it and I would be able to figure out on my own how those worked out to be as such. Here is the link to the circuit drawing.

http://s373.photobucket.com/albums/oo180/dahooligans/?action=view&current=combinationcircuit.jpg

Here's what I'm having problems with......

I don't understand is that the 2.5Amps between r2 and r3, that will remain the same right? voltage of r2 and r3 would each be 100volts?

parallel to that across R5 is 75volts, so would that make the voltage across R4 having to be 125Volts or just 25 Volts? I would guess 125 volts .

That's one dillema I have....the 2nd dillema is the ams....says 5 ams heading back to the positive so would that make the amperes across R4 and R5 2.5 amps also? and then R1 would be 5 amps, 100 volts?

2. ### mik3 Senior Member

Feb 4, 2008
4,846
63
Voltage across R4 will be 100-75=25 Volts and not 125

The current through R4 and R5 will be 2.5 because 5-2.5=2.5

voltage across R1=5*20=100V

3. ### dahooligans Thread Starter New Member

Oct 28, 2008
5
0
so will voltage across R2 be 100 volts and R3 be 100 volts also? so im guessing the total circuit voltage is 250 volts? 100 total through r2345, 100 through r1 and 50 through r6?

4. ### mik3 Senior Member

Feb 4, 2008
4,846
63
Yes you are right.

5. ### dahooligans Thread Starter New Member

Oct 28, 2008
5
0
Thank you very much Mr. Mike, that clarifies so much for me now and I'm understanding thins alot better!

6. ### dahooligans Thread Starter New Member

Oct 28, 2008
5
0
actually one more quick thing my volts aren't adding up to 250 when I do my calculations.

R1 = 20 ohms R23 = 80 ohms but I'm not sure what the ohms are for R4 and R5.

If R4 is 25V would there be 5 amps entering there? or just 2.5? im thinking 5 amps so 5 Ohms and R5 15 Ohms but the total of that combo would be 20 ohms and with the 80 it would make R2345 = 26.6 Ohms + 20 + 10 = 56 Ohms total (RT) x 5 amps = 280 volts. I think i missed a calculation?

7. ### mik3 Senior Member

Feb 4, 2008
4,846
63
The current through R4 and R5 is the same because they are in series and equals the total current of the circuit minus the current through R2 and R3, thus it will be 5-2.5=2.5Amps

Thus R4=25/2.5=10 ohms
R5=75/2.5=30 ohms

Thus R4+R5=10+30=40 ohms

and the voltage across them is

V=40*2.5=100V

8. ### Ron H AAC Fanatic!

Apr 14, 2005
7,050
657
I think you need to take another look at this.

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