# Determine the total current in the attached diagram

1. May 9, 2015

### DevonZA

Hope this is posted in the right place:

Determine the total current in the attached diagram

R parallel = 1/9.7 + 1/43 = 0.366^-1 = 2.98ohms
R series = 4.3 + 7.4 = 11.7ohms
R total = 2.98+11.7=14.68ohms

I=V/R
= 30/14.68
= 2.04A

The answer given is 4.67A, what am I doing wrong?

Thanks,
Devon

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2. May 9, 2015

### Staff: Mentor

Where does 7.4 come from and what is in series here?

If you use a number not given in the problem statement, please explain where it comes from.

There are more things in parallel.

3. May 10, 2015

### DevonZA

My apologies the 7.4 ohms should be where the second 4.3ohms in series is on the attached sketch. I drew that up late last night.

4. May 10, 2015

### CWatters

Hint: There are actually three resistors in parallel.

5. May 10, 2015

### DevonZA

I see only 2?

6. May 10, 2015

### DevonZA

Aha thank you CWatters I see that the 7.4ohm resistor is in fact in parallel.

Itotal=Vtotal/Rtotal
Rparallel = 1/9.7 + 1/4.3 + 1/7.4 = 2.12ohms
Rseries = 4.3ohms
Rt = 2.12 + 4.3 = 6.42ohms

It=Vt/Rt
It = 30/6.42
It = 4.67A

7. May 11, 2015

### CWatters

Looks right to me.