# Equivalent resistance of a circuit

• dewdrop714
In summary, the problem involves finding the equivalent resistance of a circuit with resistors of varying values and determining the current flowing through a specific resistor using the equation I = V/R. The equivalent resistance is calculated to be 25 Ohms and the current through the entire circuit is 4 Amps, but further calculations are needed to find the current through the specific resistor.
dewdrop714
1. The problem statement

http://s685.photobucket.com/albums/vv212/dewdr0p714/?action=view&current=3circuitontakehometest1.jpg

The voltage is on the left (100V) and the jagged lines are the resistors in Ohms. I need to find the equivalent resistance of the circuit and after that the current flowing through the 4 ohm resistor.

2. Homework Equations

I = V/R

3. The Attempt at a Solution

I'm not sure if I calculated these correctly...

Equiv Resistance = 7 + (10/2) + 8 + (4/2) + 3 = 25 Ohms.

For the current flowing through the 8 ohm resistor, I = V/R = 100V/25ohms = 4 Amps

Last edited:
Welcome to PF!

Hi dewdrop714! Welcome to PF!
dewdrop714 said:
The voltage is on the left (100V) and the jagged lines are the resistors in Ohms. I need to find the equivalent resistance of the circuit and after that the current flowing through the 4 ohm resistor.

Equiv Resistance = 7 + (10/2) + 8 + (4/2) + 3 = 25 Ohms.

Looks good!
For the current flowing through the 8 ohm resistor, I = V/R = 100V/25ohms = 4 Amps

8 ohm?

Anyway, that's the current through the whole circuit … you need the current flowing through just the bit of wire containing the 4(?) ohm resistor.

## 1. What is equivalent resistance?

Equivalent resistance is the total resistance of a circuit when all resistors are combined. It represents the overall resistance that the current experiences as it flows through the circuit.

## 2. How is equivalent resistance calculated?

Equivalent resistance is calculated by adding up the individual resistances in a series circuit or by using the formula 1/Req = 1/R1 + 1/R2 + 1/R3... for a parallel circuit.

## 3. Why is equivalent resistance important?

Equivalent resistance is important because it helps us determine the total current and voltage in a circuit. It also allows us to simplify complex circuits into a single equivalent resistance, making it easier to analyze and understand.

## 4. How does the placement of resistors affect the equivalent resistance?

In a series circuit, resistors are placed in a line, so the equivalent resistance is simply the sum of all the individual resistances. In a parallel circuit, resistors are placed side by side, so the equivalent resistance is less than the smallest individual resistance.

## 5. Can equivalent resistance ever be greater than the individual resistances?

No, equivalent resistance can never be greater than the individual resistances. In a series circuit, the equivalent resistance is always equal to the sum of the individual resistances. In a parallel circuit, the equivalent resistance is always less than the smallest individual resistance.

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