The discussion revolves around calculating the Thevenin voltage using the principle of superposition in an electrical circuit. Participants are examining the accuracy of calculations related to Thevenin resistance and voltage, as well as the proper application of circuit analysis techniques.
Participants express differing views on the calculations and methods used, with some corrections and clarifications being made, but no consensus is reached on the final correctness of the calculations.
There are unresolved issues regarding the assumptions made in the calculations, particularly in the treatment of voltage and current sources during the analysis.
gneill said:Check your Thevenin resistance. When you calculated 60 || 30 you seem to have ended up with 15, although you did it correctly elsewhere.
Check your ##V_{th1}## calculation. You have a voltage divider and shouldn't end up with the same voltage as the source driving it on its output.
For ##V_{th3}##, when you suppress the 1.2 A source you remove it, not short it. And suppressing the 18 V supply shorts it. Draw the remaining circuitry. You'll see that the 0.25 A supply does make a contribution to Vth (it's still in parallel with a 20 Ohm resistor).
Awesome. Thanks so muchgneill said:Right. When you suppress sources, currents are replaced by open circuits, voltages by short circuits.