Relative Brightness of Light Bulbs in Series & Parallel Connection

  • Context: Undergrad 
  • Thread starter Thread starter Empire
  • Start date Start date
  • Tags Tags
    Brightness Relative
Click For Summary
SUMMARY

The discussion centers on the relative brightness of five identical light bulbs arranged in a combination of series and parallel connections. Light bulbs A and B are connected in parallel, while bulbs C and D are in series and connected in parallel with bulb E. The conclusion drawn is that the brightness of the bulbs is equal, represented as A=B=E=C+D. This conclusion is based on the principles of current distribution in parallel and series circuits, where the total current through the branches is equal and the voltage across each bulb must be considered to determine brightness.

PREREQUISITES
  • Understanding of electrical circuits, specifically series and parallel connections.
  • Knowledge of Ohm's Law and current distribution in circuits.
  • Familiarity with voltage calculations in series and parallel configurations.
  • Basic concepts of light bulb brightness as a function of current and voltage.
NEXT STEPS
  • Study the principles of series and parallel circuits in detail.
  • Learn about Ohm's Law and its application in circuit analysis.
  • Explore voltage division and current division rules in electrical circuits.
  • Investigate how different configurations affect the brightness of light bulbs in practical applications.
USEFUL FOR

Electronics students, electrical engineers, and anyone interested in understanding circuit behavior and light bulb brightness in series and parallel arrangements.

Empire
Messages
3
Reaction score
0
Assuming there are five identical light bulbs. Light bulb C and D are in a series connection. C and D are in a parallel connection with E. Light Bulb A and B are in a parallel connection. The two parallel connections are wired in a series connection. What would be their relative brightness? I'm thinking that A=B=E=C+D

********************
|----power---------------|
|*******************|
|*******************|
|**|--A--|***|-C-D-|**|
|---|****|----|****|---|
***|--B--|***|--E--|***
********************


in a parallel connection, It=I1+I2, therefore, A=B. In a seriese connection, The total current equals the individual currents, so C=D. Back to the parallel connection, C+D=E. In a series, they are all equal, so (A+B)=(E+C+D). Therefore...A=B=E=C+D. My friend said that it might be: C^D<A^B<E

Any suggestions?
 
Physics news on Phys.org
EDIT: Ignore this post! I misread your diagram; Chi Meson has it right in the next post.

Empire,

Think of it more as an electrical problem first, and then worry about brightness.

Suppose your power source is a voltage of 100V.

What's the voltage across the B-E branch?

So what's the voltage across B? Across E?

What's the voltage across the A-CD branch?

So What's the voltage across A (be careful!)? Across CD ? Across C? Across D?
 
Last edited:
Another way to think of it: The brightest bulb will have the most current going through it.

Obviously,the total current through the entire A/B unit will equal the total current through the C/D/E unit. And the current through A and B is equal, and each gets exactly half the total current.

So ask yourself, where will more current go, through the C-D branch, or the E branch?
 

Similar threads

  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 14 ·
Replies
14
Views
22K
  • · Replies 57 ·
2
Replies
57
Views
15K
Replies
10
Views
2K
  • · Replies 6 ·
Replies
6
Views
809
Replies
1
Views
3K
  • · Replies 14 ·
Replies
14
Views
3K
  • · Replies 13 ·
Replies
13
Views
1K
  • · Replies 13 ·
Replies
13
Views
3K