Resistors in seris and in parallel

  • Context: High School 
  • Thread starter Thread starter Moninder
  • Start date Start date
  • Tags Tags
    Parallel Resistors
Click For Summary
SUMMARY

This discussion focuses on calculating voltage, resistance, and current for resistors in series and parallel configurations. The user initially calculated total resistance incorrectly, arriving at 77.92 ohms and a total current of 1.54A. The correct approach involves using Ohm's Law to determine voltage across equivalent resistances, specifically for the 7.2258 ohm equivalent resistance and the parallel combination of 72 ohm and 45 ohm resistors. The voltage across individual resistors must be calculated using their respective resistances and the total current.

PREREQUISITES
  • Understanding of Ohm's Law (V = IR)
  • Knowledge of series and parallel resistor configurations
  • Ability to calculate equivalent resistance for series and parallel circuits
  • Familiarity with basic electrical units (voltage, current, resistance)
NEXT STEPS
  • Learn how to calculate equivalent resistance in complex circuits
  • Study the application of Ohm's Law in series and parallel circuits
  • Explore voltage division and current division principles
  • Investigate the impact of resistor tolerances on circuit performance
USEFUL FOR

Electronics students, electrical engineers, hobbyists working on circuit design, and anyone interested in understanding resistor behavior in electrical circuits.

Moninder
Messages
22
Reaction score
0
I have this question
v0ynsWi.jpg

I need to Find Voltage, Resistance and Current in all resistors and total.
This is what I did so far.
Added 13ohms +15 ohms, then took all 3 of those and made it into one, whihc gave me 7.2258ohms.
Did the same for the 72 and 45 to get 27.7 ohms.
Then found the total resistance as 77.92 ohms. Found I total , current to be 1.54A
And for the 19ohm resistors I got V=29.26V I=1.54A
For 24ohm, V=36.96 I=1.54A
And I think for the 32 ohm V=29.26 I=0.91A
For 72ohm and 45 ohm V=27.7ohm and if that is it, should total current equal 1.54 instead of 0.88A?
 
Physics news on Phys.org
I take it we are supposed to psychically devine what voltage is across the string? :smile:
 
phinds said:
I take it we are supposed to psychically devine what voltage is across the string? :smile:

I just did, it's 120 V.

The voltage across the 32V resistance is wrong.
To determine the voltage across parallel resistances, you first use ohms law on the equivalent reistance, so you multiply the equivalent resistance (which was 7.2258 ohm), with the total current, to get the voltage across all the parallel resistances. Then you find out all the currents through individual resistances by using ohms law on the individual resistances.

This goes for the 72 ohm in parallel with 45 ohm too.
 

Similar threads

  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
925
  • · Replies 11 ·
Replies
11
Views
3K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 7 ·
Replies
7
Views
2K
Replies
3
Views
2K
  • · Replies 105 ·
4
Replies
105
Views
13K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 8 ·
Replies
8
Views
3K