# Equivalent resistance if the values of the two resistances

• XodoX
In summary, to find the equivalent resistance of resistors in series, you simply add their values. For resistors in parallel, you can use the equation (1/Requivalent) = (1/R1) + (1/R2) + ... + (1/Rn) or the simplified equation for two resistors, Requivalent = (R1 x R2) / (R1 + R2). Using these equations, we can find the equivalent resistance for the given values of resistors in series and parallel.

#### XodoX

Two resistors are in series. Find the equivalent resistance if the values of the two
resistances are as follows.
a) 10 [Ω] and 20 [Ω].
b) 100 [Ω] and 1 [MΩ] (M stands for “Mega” or million).
c) 3.0 [kΩ] and 6.7 [kΩ] (k stands for “kilo” or thousand).
d) 400 [Ω] and 1 [Ω].

Repeat the above problem, assuming that the resistors are in parallel.

Can anybody hel me with this, please? I have no idea how to start/do this.

Thank you!

To start you off, what do you know about how to find equivalent resistance of resistors in series and parallel?

parallel has the same voltage and the current in series stays the same?

Series resistors:

Requivalent=R1+R2+R3+...+Rn

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Parallel resistors:

( 1/ Requivalent) = ( 1 / R1) + ( 1/ R2) +...+ ( 1/ Rn)

OR you can use the following equation if you have two parallel resistors:

Requivalent=$$\frac{R1 \times R2}{R1 + R2}$$

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So I just add them? a) would be 30 then.
Thank you, that works:)

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## 1. What is equivalent resistance?

Equivalent resistance is the combined resistance of two or more resistors in a circuit. It represents the total resistance that a current experiences when passing through multiple resistors in series or parallel.

## 2. How is equivalent resistance calculated?

The equivalent resistance can be calculated using Ohm's Law, which states that resistance (R) is equal to voltage (V) divided by current (I). In series circuits, the equivalent resistance is the sum of all individual resistances. In parallel circuits, the reciprocal of the equivalent resistance is equal to the sum of the reciprocals of individual resistances.

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

In a series circuit, the resistors are connected in a single path, so the same current flows through each resistor. In a parallel circuit, the resistors are connected in multiple paths, so the current is divided among them. This affects the calculation of equivalent resistance for each type of circuit.

## 4. How do the values of the two resistances affect the equivalent resistance?

The values of the two resistances directly affect the equivalent resistance in both series and parallel circuits. In series circuits, increasing the resistance of one resistor will increase the overall equivalent resistance. In parallel circuits, increasing the resistance of one resistor will decrease the overall equivalent resistance.

## 5. Why is understanding equivalent resistance important in circuit analysis?

Equivalent resistance is an important concept in circuit analysis because it allows us to simplify complex circuits into a single equivalent resistance, making it easier to calculate the overall current and voltage in the circuit. It also helps in designing circuits with the desired resistance values and in troubleshooting circuit problems.