Can Adding Resistance to a Load Increase Maximum Power?

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SUMMARY

The discussion centers on the Maximum Power Theorem, which states that to achieve maximum power transfer from a source to a load, the load resistance must match the source resistance. Participants clarify that while increasing load resistance can lead to a higher load voltage, it simultaneously reduces load current. The relationship between source impedance and load impedance is crucial, and the optimal load impedance for maximum power transfer can be determined using calculus to differentiate the power equation. Participants emphasize the importance of calculations to understand these dynamics fully.

PREREQUISITES
  • Understanding of the Maximum Power Theorem
  • Basic knowledge of electrical circuits and impedance
  • Familiarity with Ohm's Law and power calculations
  • Basic calculus for differentiating equations
NEXT STEPS
  • Study the Maximum Power Transfer Theorem in detail
  • Learn how to calculate load voltage and current based on varying resistances
  • Explore complex impedance and its impact on power transfer
  • Practice calculus techniques for optimizing power equations
USEFUL FOR

Electrical engineers, physics students, and anyone interested in optimizing power transfer in electrical circuits will benefit from this discussion.

Idea04
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I need some help to understand the maximum power theorom. From what I understand it states that in order to get maximum power from a source you have to match the resistance of the source to the resistance of the load. Now what i don't understand is how could adding resistance to a load generate more power. I thought electric power traveled a path to least resistance. And if the resistance of the source is high, let's say a kilo-ohm or mega-ohm, wouldn't the power from the source dissipate to nothing if it came across a load of such high resistance. Especially if the voltage from the source was low (lets ay under 3 volts).
 
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Idea04 said:
I need some help to understand the maximum power theorom. From what I understand it states that in order to get maximum power from a source you have to match the resistance of the source to the resistance of the load. Now what i don't understand is how could adding resistance to a load generate more power. I thought electric power traveled a path to least resistance. And if the resistance of the source is high, let's say a kilo-ohm or mega-ohm, wouldn't the power from the source dissipate to nothing if it came across a load of such high resistance. Especially if the voltage from the source was low (lets ay under 3 volts).

Classic problem -- good for you to understand it. *Given* some source Z (complex in the general case, not just resistive), if you load it with higher than that Z, you get a higher load voltage, but a lower load current. Calculate the result, and please show us your work.

And if you load the source with a lower Z, you get a higher load current, but a lower load voltage. Calculate the result, and please show us your work.

Now, use calculus (differentiate the right equation) to show what the best Zload is (again, complex) for maximum power transfer, given some pre-set source impedance. Please show us your work.
 

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