Equivalent resistance if the values of the two resistances

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Discussion Overview

The discussion revolves around finding the equivalent resistance of two resistors in both series and parallel configurations. Participants explore the calculations required for specific resistor values and seek clarification on the underlying principles of these configurations.

Discussion Character

  • Homework-related, Technical explanation

Main Points Raised

  • Post 1 presents a problem involving two resistors in series and parallel, asking for the equivalent resistance for various pairs of resistor values.
  • Post 2 prompts the original poster to consider what they know about calculating equivalent resistance in series and parallel.
  • Post 3 suggests that in parallel configurations, the voltage remains the same while the current is constant in series configurations.
  • Post 4 provides the formulas for calculating equivalent resistance in both series and parallel arrangements, including a specific formula for two parallel resistors.
  • Post 5 confirms the addition of resistances in series, calculating the equivalent resistance for the first pair as 30 [Ω].

Areas of Agreement / Disagreement

Participants do not reach a consensus on the calculations for all resistor pairs, and the discussion remains open with some uncertainty regarding the application of the formulas.

Contextual Notes

Some participants may have varying levels of familiarity with the concepts of series and parallel resistors, which could affect their understanding of the calculations.

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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. :confused:

Thank you!
 
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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

______________________________________________________

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}
 
Last edited:


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

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