Understanding Joule's Law and Power: How Does It Relate to Heat and Resistance?

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SUMMARY

This discussion clarifies the relationship between Joule's Law, power, and heat generation in resistors. Joule's Law, expressed as Q=I²RT, indicates that heat (Q) generated is proportional to resistance (R) when current (I) and time (t) are constant. When resistors are connected in series, the total resistance increases, leading to greater heat generation compared to parallel connections, where the total resistance decreases. The distinction between Joule's heat and power is emphasized, with power defined as the rate of change of energy.

PREREQUISITES
  • Understanding of Joule's Law (Q=I²RT)
  • Knowledge of electrical resistance in series and parallel circuits
  • Familiarity with the concepts of power and energy in electrical systems
  • Basic principles of current and voltage relationships
NEXT STEPS
  • Explore the implications of Joule's Law in practical electrical engineering applications
  • Learn about the calculation of power in AC circuits using RMS values
  • Investigate thermal management techniques in resistor design
  • Study the effects of varying resistance on circuit performance in series and parallel configurations
USEFUL FOR

Electrical engineers, physics students, and anyone interested in understanding the principles of heat generation in electrical circuits and the relationship between power and resistance.

I&Tstudent
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Hello, i want to ask 2 questions:
1-what is the difference between joule's heat and power?
2-We have 2 different resistors.How joule's heat ,which is created in them, will change if they connect to a steady voltage source:(a)in series,(b)in parallel
Thank you
 
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What are your thoughts on the subject?

Is Joule's heat just energy or something else? How does energy relate to power?


Also, how is total resistance affected when resistors are in series/parallel?
 
total resistance in series is Rt=R1+R2+...+Rn and in parallel 1/Rt=1/R1+1/R2+...+1/Rn.
Joule's law sais Q=I^2*R*t where Q the heat generated by a constant current.If (I) and (t) are constant Q is proportionate to R so in series Q will increase more than when the resistors are in parallel.Correct?
 
I&Tstudent said:
total resistance in series is Rt=R1+R2+...+Rn and in parallel 1/Rt=1/R1+1/R2+...+1/Rn.
Joule's law sais Q=I^2*R*t where Q the heat generated by a constant current.If (I) and (t) are constant Q is proportionate to R so in series Q will increase more than when the resistors are in parallel.Correct?

Wouldn't the total resistance in parallel be less than in series?
 
rock.freak667 said:
Wouldn't the total resistance in parallel be less than in series?
thats what i said
 
I&Tstudent said:
thats what i said

Sorry I read that incorrectly. But you are correct.

and remember that power is the rate of change of energy.
 

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