https://en.wikipedia.org/wiki/Maximum_power_transfer_theorem

My brother writes poker articles and books. I showed him that MPTT captures perfectly what constitutes a "good" card session.

ak

 

I don't know if it helps the TS grasp the issue but you run into a similar thing when you pair a generator to a load. Both have some impedance. The most power you can drive into the load happens when they both have the same impedance. If the load is bigger than that (less resistance), the voltage from the generator falls off. The current goes up all the way to a dead short, but the power dissipated by the load goes down because of the voltage sag. If the load is smaller (higher resistance) than the generator impedance, the voltage across the load increases but the current drops too much and again the power goes with it.

Point is, there's an optimum load resistance, and the response to a change in load resistance depends on which side of the peak you're on.

Are you sure about this?

Are you REALLY saying that if I want to get the most power possible to a 100 Ω load that my generator needs to have 100 Ω of impedance?

Let's test it out.

I have a three 100 V generators available to me. For simplicity let's say that they have resistive impedances of 0.1 Ω, 1.0 Ω, and 10 Ω. I also have three loads that also happen to have resistances of 0.1 Ω, 1.0 Ω, and 10 Ω.

You say that the most power I can get into the 10 Ω load is with the generator that has 10 Ω of impedance. I say that if I use the 0.1 Ω generator I will get nearly four times the power into that same load.

Run the numbers and see what you find.

 

Yep, many people misunderstand the max power theorem that way. If the load impedance is fixed, and you can vary rhe source impedance, you always get max power to the load with the lowest source impedance.

The max power theorem applies when the source impedance is fixed and load impedance can be varied.

Bob

 

Are you REALLY saying that if I want to get the most power possible to a 100 Ω load that my generator needs to have 100 Ω of impedance?

No, but I guess I wasn't very clear. I was thinking of a small wind generator or solar panel or the like, and choosing a load that maximizes the power drawn from that source.

The max power theorem applies when the source impedance is fixed and load impedance can be varied.

What he said.

 

https://en.wikipedia.org/wiki/Maximum_power_transfer_theorem

My brother writes poker articles and books. I showed him that MPTT captures perfectly what constitutes a "good" card session.

ak

As a former hardcore poker player, I'm curious about this. Can you elaborate?

 

In this case, "power" is the amount of enjoyment in a poker session. Continuously beating a lesser player results in lots of winnings (electron flow), but no feeling of satisfaction or achievement - no pressure (voltage); you're not picking on someone your own size, you're punching below your weight class, etc. Continually losing to a better player might teach you a lot about the game, but getting clobbered never leaves a good taste in the mouth. If voltage is effort and money flow is current, then maximum power happens when the effort and the winnings are in balance. As above, no effort and lotsa cash is relatively low fun. So is lotsa effort and no cash. Maximum power (enjoyment) is transferred to the player when the player and the game are well matched - the impedance of the source equals the impedance of the load.

ak

 

The max power theorem applies in the case when the source impedance is fixed.
In this case the max power is delivered to the load when the load impedance matches that of the source.

If the load impedance is fixed, max power is supplied when the source impedance is zero.

 

In this case, "power" is the amount of enjoyment in a poker session. Continuously beating a lesser player results in lots of winnings (electron flow), but no feeling of satisfaction or achievement - no pressure (voltage); you're not picking on someone your own size, you're punching below your weight class, etc. Continually losing to a better player might teach you a lot about the game, but getting clobbered never leaves a good taste in the mouth. If voltage is effort and money flow is current, then maximum power happens when the effort and the winnings are in balance. As above, no effort and lotsa cash is relatively low fun. So is lotsa effort and no cash. Maximum power (enjoyment) is transferred to the player when the player and the game are well matched - the impedance of the source equals the impedance of the load.

ak

I was thinking your comment was more about a mismatch between hands. The best hand I've ever had was a royal flush. We were in grade school and playing at lunch, betting potato chips. I thought I'd win every chip on the table! Nobody else had a hand worth anything and no one bet against me. My royal flush was worth next to nothing. I needed somebody with a full house or 4-of-a-kind, to match the "power" of my hand.