Brightness of Light Bulbs in a Circuit

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SUMMARY

The discussion centers on the brightness of light bulbs in a circuit configuration where four bulbs are connected in parallel and one bulb is connected separately. It is established that if all bulbs are identical, the brightness is determined by the voltage drop across each bulb. The bulb with the highest voltage drop will glow brighter, as brightness is directly proportional to the power delivered to the bulb. The conversation emphasizes that knowing the resistance values is unnecessary for comparing brightness, as the focus is on voltage distribution in the circuit.

PREREQUISITES
  • Understanding of basic electrical circuit concepts
  • Knowledge of Ohm's Law and its application in circuits
  • Familiarity with series and parallel circuit configurations
  • Concept of power dissipation in resistive components
NEXT STEPS
  • Research voltage drop calculations in parallel and series circuits
  • Learn about power dissipation in resistors and its effect on brightness
  • Explore practical experiments with different light bulbs and voltage sources
  • Study the impact of non-identical bulbs on circuit behavior and brightness
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Electrical engineering students, hobbyists experimenting with circuits, and educators teaching basic electronics concepts.

ghostbuster25
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Quick question, if i had a circuit of 5 light bulbs whereby 4 were running parellel in a sequence and one was running seperatly, would one be brighter than the others?
sorry if it is hard to visulise :)
 
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I assume from your question that 4 bulb connected in parallel is in series with 5th bulb to a voltage source.
Now assuming all bulbs are identical, i.e., they have same resistances (say x) you can find the total resistance. And if you find voltage drop across these bulbs, you can find which bulb will be brighter.
 
so shall i just substitute x into where the values of resistance would be. I am not given any values for anything
 
Assume each bulb has resistance R and the whole circuit is driven by a source that produces V volts between its two terminals. Remember that the brightness is directly proportional to the power delivered to the bulb (assuming no or identical power loss).

Using these, you should be able to compare their brightnesses.
 
No need to know the value of resistance, because you have to find which bulb is brighter and not how much right?
By simple common sense we know that the bulb with more voltage across it glows brighter. So you may check across which bulb more voltage drop will occur.
 
n.karthick said:
No need to know the value of resistance, because you have to find which bulb is brighter and not how much right?

Even if you knew the value of the resistance, you will need to know much more to actually calculate a value for luminous flux or intensity. Comparison is the only sensible thing that I can see being done given only these pieces of information.

n.karthick said:
By simple common sense we know that the bulb with more voltage across it glows brighter. So you may check across which bulb more voltage drop will occur.

That is only true if the bulbs are identical. As I said the brightness is directly proportional to the power dissipated by the resistor inside the bulb. That's not a function of only the voltage across it. If you aren't convinced, you can easily try this by using two different light bulbs and a 9V battery.
 
so am i right in believing it to be bulb p? the one on its own but in parallel with the others
 
ghostbuster25 said:
so am i right in believing it to be bulb p? the one on its own but in parallel with the others

Which one are you referring to as bulb p?
 

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