# How do I solve this complex circuit with resistors in series and parallel?

• Engineering
• CL1349
In summary, the conversation discussed finding all resistance, voltage, current, and power values for a circuit using the voltage and current divider rules. The circuit was simplified to equivalent values and the total current and power were calculated. The conversation also addressed how to tackle the resistors in the middle of the circuit by using the voltage and current divider rules.
CL1349

## Homework Statement

Find all resistance, voltage, current, and power values for the circuit.

## Homework Equations

I = V/R V = IR R = V/I

Voltage Divider Rule
Current Divider Rule

## The Attempt at a Solution

I simplified the circuit down to equivalent values. Sorry for the poor image of the circuit.

I turned the R1 and R2 parallel combo into Req1, = 60 ohms.

Then added the series combo of R6 + R7 in the middle, Req2 = 120 ohms.

The parallel combo of R4 and R5 at the top, Req3 = 160 ohms.

Added the series combo of R3 + Req3, Req4 = 240 ohms.

Solved the parallel combo of Req4 and Req2, Req5 = 80 ohms.

Then I'm left with 3 resistors in series, Req 1 + Req5 + R8, RT= 220 ohms.

I found total current, IT= VT/RT, 660 V/220 ohms, = 3 A

Found total power, PT= IT*VT, 3A*660V = 1980 A

Then I tried to find the current of R1 by using the current divider rule. I came out with 2 A.Now, I am wondering if I did it right and how do I tackle those resistors in the middle, do I just use voltage divers/current dividers?

If anyone can check if I did it right or offer advice, it would be much appreciated. Thanks.

#### Attachments

• Circuit.png
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Last edited:
That picture is quite bad, but the numbers look OK.

Remember that current in series is the same everywhere, so after the 3A flows into the first parallel pair, 3A will flow out of it too (since you essentially have 3 groups of resistances in series in this diagram).

Then, just keep in mind that you can reduce the middle clump to a parallel pair (top = 90 + 480||240, bottom = 80 + 40) to find out how the current splits, and then when you know the current in the top path, you can again see how it would split for the top parallel pair.

## 1. What is a complex circuit?

A complex circuit is an electrical circuit that consists of multiple interconnected components, such as resistors, capacitors, and inductors, that work together to perform a specific function.

## 2. How do I calculate the total resistance in a complex circuit?

To calculate the total resistance in a complex circuit, you can use Ohm's law (R = V/I) or the equivalent resistance formula (1/Rt = 1/R1 + 1/R2 + ... + 1/Rn). You will need to know the individual resistances of each component in the circuit.

## 3. What is the difference between a series and parallel circuit?

In a series circuit, the components are connected one after another in a single loop, so the current remains the same throughout. In a parallel circuit, the components are connected in separate branches, so the current is divided among the branches.

## 4. How do I troubleshoot a complex circuit?

To troubleshoot a complex circuit, you can use a multimeter to check for continuity, voltage, and resistance at different points in the circuit. You can also visually inspect the components for any signs of damage or loose connections.

## 5. Can I simplify a complex circuit?

Yes, it is possible to simplify a complex circuit by using equivalent circuits or simplification techniques like Thevenin's and Norton's theorems. However, the simplification may affect the accuracy of the circuit's performance, so it is important to carefully consider the trade-offs before making any changes.

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