Wednesday, February 16, 2022

Z matching part 2

If you read the first part of the tutorial I linked in my last post this may be your uh hah moment. I will post one sim that tells a lot about web wisdom and reality. It will also lead to more questions. I hope to do another post to continue the story of Z matching. The journey continues.

In the simulator you can set the generator Z and it will not be displayed. For this sim I set the internal Z to zero and placed a 50 ohm resistor in series with the load. Remember Power is equal to current squared time resistance. In both cases I have the same load so the power increase or loss is a square function. I(r5) is more than twice I(r2) so the power delivered is more than four times as much. Look at the voltage delivered to the loads. V1_out is one half the generator voltage wish tells Zg = Zl. Web wisdom  states max power transfer is when Zg = Zl but they do not finish the story. The tutorial begins with that as the first step on the journey. The second step is to understand the power loss internal to the generator is one half of the available which is not acceptable. 

1st step = Max power transfer Zg = Zl

2nd step = The generator is going to at least waste a lot of power and possibly smoke

3rd In some cases the power transfer is more efficient when a PROPER Z mismatch is used.

Years ago we were taught to use a MINIMUM of a ten to one ratio.

Later they said we should use a MINIMUM of 100 to one.

When do we really need be concerned about matching and how do we apply the matching for best advantage? 

To be continued ..........



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