Thevenin equivalent (symbolic circuit calculation)

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Casper Hansen
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Homework Statement


I have trouble to find the right procedure to transform the circuit below to a thevenin equivalent.
I am looking for a symbolic solution a step by step guidance of where to start and how to add/locate all the impedance in series and parallel in order to calculate the sum of Z seen from point A and B
Circuit schematic with an AC source between nodes A and B; Z1 connects from A to a junction, Z2 connects from B to the same junction, Z4 runs from that junction to the right-hand wire, Z3 sits above node A and Z5 below node B, both joined to a common wire tied to GND1.

Circuit schematic of an AC voltage source drawn as a circle with a sine wave symbol, labeled AC, with its top terminal wired to a rectangular impedance block labeled SumZ.

The Attempt at a Solution


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I have a hard time see which impedance are in series and parallel, as Z5, Z4 and Z3 forms a star connection to GND?

Circuit schematic of an AC source feeding a bridge network: Z3 from node A down to a centre node, Z5 from the centre node down to node B, Z1 from A to a right node, Z4 from the centre node to that right node, and Z2 from the right node to B.


Would the solution be to make a form of star/delta transformation of the circuit in order to calculate the circuit?
 
Attachments
  • Circuit schematic of an AC voltage source drawn as a circle with a sine wave symbol, labeled AC, with its top terminal wired to a rectangular impedance block labeled SumZ.
    upload_2018-10-1_15-35-31.png
    846 bytes · Views: 529
  • Circuit schematic with an AC source between nodes A and B; Z1 connects from A to a junction, Z2 connects from B to the same junction, Z4 runs from that junction to the right-hand wire, Z3 sits above node A and Z5 below node B, both joined to a common wire tied to GND1.
    upload_2018-10-1_15-35-42.png
    2 KB · Views: 577
  • Circuit schematic of an AC source feeding a bridge network: Z3 from node A down to a centre node, Z5 from the centre node down to node B, Z1 from A to a right node, Z4 from the centre node to that right node, and Z2 from the right node to B.
    upload_2018-10-1_15-42-33.png
    2.2 KB · Views: 507
Last edited:
You have to define the nodes between which you want the Thevenin equivalent. Without that your question has no answer.

Also, we don't DO "step by step" instructions. YOU do a step by step analysis and tell us when you get stuck.
 
phinds said:
You have to define the nodes between which you want the Thevenin equivalent. Without that your question has no answer.

Also, we don't DO "step by step" instructions. YOU do a step by step analysis and tell us when you get stuck.

My post have been updated with nodes A and B
 
Casper Hansen said:
My post have been updated with nodes A and B
Then a first step of getting the Thevenin Equivalent voltage should be REALLY easy. What is it?
 
phinds said:
Then a first step of getting the Thevenin Equivalent voltage should be REALLY easy. What is it?
If i know the voltage but need to find the sum of impedances in order to calculate the current
 
Casper Hansen said:
If i know the voltage but need to find the sum of impedances in order to calculate the current
You did not answer my question.
 
Casper Hansen said:
If i know the voltage but need to find the sum of impedances in order to calculate the current
You can find the current by using standard circuit analysis methods: basic KVL & KCL, Nodal Analysis, Mesh analysis... Take your pick.

Edit: Or, as you've stated, you could use a star-delta transform to begin reduction of the resistor network.
 
phinds said:
You did not answer my question.
Sorry I did not quite get what you are asking for?
 
Casper Hansen said:
Sorry I did not quite get what you are asking for?
"Then a first step of getting the Thevenin Equivalent voltage should be REALLY easy. What is it?" is asking you for the Thevenin Equivalent voltage. I don't see how I could have asked it any more plainly. What is the Thevenin Equivalent voltage, given the circuit you have drawn with the nodes you have drawn? Just LOOK.