Solve Combination Circuit Homework: Req, IT, Current & Voltage

[dropgigawatt]

Homework Statement

Determine the R_eq, I_T, and the current and voltage across each resistor. Collapse each drawing into one resistor that equals R_eq. Find the total power used by the circuit. Also determine the voltage, current, and power for each individual resistor.

The one I'm having trouble with:

Homework Equations

R_eq = R₁+R₂+R₃...
1/R_eq = 1/R₁+1/R₂+1/R₃...
V = IR
P = IV

The Attempt at a Solution

I combined B and C into BC (4 Ω) and then combined that with F to make BCF (2 Ω). This would give me the following resistances: R_A = 2 Ω, R_E = 6 Ω, R_BCF = 2 Ω, R_G = 2 Ω, and R_D = 5 Ω. That would make R_eq = 17 Ω since all these are now in series.

When trying to calculate the current of the whole circuit... I = V/R_eq = 40/17 = 2.35 A

My teacher posted that the total current should be 4 A. I'm not sure where I messed up.

 

[collinsmark]

Homework Statement

Determine the R_eq, I_T, and the current and voltage across each resistor. Collapse each drawing into one resistor that equals R_eq. Find the total power used by the circuit. Also determine the voltage, current, and power for each individual resistor.

The one I'm having trouble with:

Homework Equations

R_eq = R₁+R₂+R₃...
1/R_eq = 1/R₁+1/R₂+1/R₃...
V = IR
P = IV

The Attempt at a Solution

I combined B and C into BC (4 Ω)

That's a fair start.

and then combined that with F to make BCF (2 Ω).

There is where the problem is!

You can't treat BC and F as being parallel with each other. There are resistors E and G in the way which prohibit that!

However, what you can do is combine E, F and G, all in series.

After that, you have parallel resistors that you can combine: BC and EFG. (And then deal with a couple more series resistors A and D even after that.)

 

[dropgigawatt]

AH! That makes so much sense! Thanks!