Maximum power transfer

[gar]

120106-2213 EST

This question is for those that do not already know the answer, but like a thought provoking challenge.

Given an ideal constant voltage source of 100 V and an internal resistance of 5 ohms what is the load resistance that will produce the maximum power dissipation in the load resistance? What is the current and power in the load at maximum power transfer? How do you solve this problem?

How was this related to Edison's concept of a parallel power distribution system?

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[Speedskater]

For maximum power transfer, load impedance should equal source impedance.

 

[Besoeker]

For maximum power transfer, load impedance should equal source impedance.

Yes, but can you explain how it is calculated?
I think that's what Gar was getting at.

 

[steve66]

Sidenote: Is max. power transfer always a good thing?

Hint: What is the efficiency at maximum power transfer?

 

[Joethemechanic]

120106-2213 EST

Is that a date? And if so, for what?


And does this have something to do with Brocton Mass?

It was mass wasn't it?

This is an answer requiring thought isn't it?

I hate thought,

Time for a case of beer and watching the ballgame

 

[Joethemechanic]

120106-2213 EST

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OK document creation date.

Makes sense when I use the right format to look at it

YYMMDD and 24hour time

If you were a pilot you would be using GMT instead of EST :happyyes:

I always make sure I understand everything on a document before I start calculating.

Hard to answer if the question isn't understood

 

[gar]

120107-1538 EST

Joethemechanic:

My date and time code provides a monotonic address in date and time. Very useful for various reasons.

In DOS when I do a sort for files by name in QDOS 3 a very good sort is obtained based on the standard ASCII character set, and names occur in a monotonic order based on the binary code for the character.

Not so in Windows. I really do not know what algorithm they use for sort order of filename.

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[Joethemechanic]

120107-1538 EST

Joethemechanic:

My date and time code provides a monotonic address in date and time. Very useful for various reasons.

In DOS when I do a sort for files by name in QDOS 3 a very good sort is obtained based on the standard ASCII character set, and names occur in a monotonic order based on the binary code for the character.

Not so in Windows. I really do not know what algorithm they use for sort order of filename.

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It's a good one. When I started in business I let my (now ex) wife name all my files, invoices, whatever. Well she used MMDDYY format. Me not thinking, never took notice. Until the year changed :ashamed1:

 

[gar]

120108-1021 EST

Speedskater:

In your post numbered #2 how do you prove that statement?

Suppose I change the source to a 100 V RMS 60 Hz sine wave with an internal impedance of 5 ohms resistance in series with a 10 H inductor, then what load results in maximum power transfer to the load?

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[topgone]

There is a very simple worded explanation on this one:

Power being a product of actual amps and voltage across the load resistor will be maximum if the voltage across and the current running through the resistance is maxed! That said, the maximum power transfer will occur when the total internal impedance of the source equal that of the load impedance! Crystal!

 

[gar]

120108-1101 EST

topgone:

In my post numbered 9 what is the maximum power in the load by your definition?

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[Besoeker]

120108-1021 EST

Speedskater:

In your post numbered #2 how do you prove that statement?

Suppose I change the source to a 100 V RMS 60 Hz sine wave with an internal impedance of 5 ohms resistance in series with a 10 H inductor, then what load results in maximum power transfer to the load?

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Big inductor......

 

[topgone]

Big inductor......

Very big inductor coil indeed! X_L = 2 x pi x 60 x 10H = 3,769.911 ohms! Even with a 5-ohm resistance in series,the total source impedance will be 3,769.914 ohms!

Total power transferred at max power transfer is 1.32453331060998 watts

 

[gar]

120108-2030 EST

topgone:

Your value is nothing close to maximum power transfer.


Speedskater:

I still want to know how you prove your statement.

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[Joethemechanic]

For maximum power transfer, load impedance should equal source impedance.

I think I use to know this, from audio and RF circuits


Mr Colombo's 9 grade electronics class 1974. He was great


Am I on the right track?

 

[Joethemechanic]

Wow, how long is a 60Hz wave? In meters I guess. Are they even measured in meters with that low a frequency?

And how about the 25Hz railroad traction stuff, I'll bet that is one serious long wave.

 

[Joethemechanic]

wavelength = 300 / frequency in MHz


darn unit conversions

 

[Joethemechanic]

5 million meters,,,,,,,,,,,,


I better double check my calculations

That's 5,000 kilometers

Can that be right?

 

[Joethemechanic]

3,106.86 miles. That is a wavelength to span the North-American continent from east to west.

Am I even going down the right road here? Or am I way off base?

 

[ActionDave]

That sounds a little long.