Can I please get some help with this question? please.im very stuck for my quiz!!?I would really appreciate it

Question

1.)
When a given source circuit (Circuit S) is connected to a load resistor, RL, under what condition will the maximum power transfer to the load resistance from the source circuit occur?
A. If the load resistor is an open circuit, RL = ∞.
B. If the load resistor is a short circuit, RL = 0.
C. If the load resistance is one half of the Thevenin equivalent resistance of Circuit S.
D. When the load resistance is equal to the Thevenin equivalent resistance of Circuit S.

and.....

2.)
Mesh current analysis can be used for:
A. Any circuit.
B. Only circuits containing independent voltage sources.
C. Any planar circuit.
D. Whenever node voltage analysis can be used.



3.)
For the current source in a Norton equivalent circuit, the magnitude of the current can be determined by placing a short circuit across the terminals of the circuit, and determining the current through the short circuit. True or False

Answer 1

1.) D. When the load resistance is equal to the Thevenin equivalent resistance of Circuit S. (page 112 "The analysis and design of linear circuits 5th edition")

2.) C. Any planar circuit. (page 81 "The analysis and design of linear circuits 5th edition")

3.) True (page 100 "The analysis and design of linear circuits 5th edition")


these ARE the answers :D

Answer 2

1) For each of the four possible answers, calculate the voltage across RL and the current through RL. Multiply together to get the power dissipated by RL and pick the one that gives the highest.

1A) For an open circuit, RL = infinity. So, the current through RL is zero, no matter what voltage is impressed across it. So, the power is zero. (volts * current)
1B) For a short circuit, the voltage is zero. So, even if the current is high, the power dissipated through RL is zero. (BTW, superconductors have essentially zero resistance and can transmit large amounts of current.).
1C) Calculate the Thevenin reistance of S. This resistance can then be treated as being in series with RL. This then looks like a two-resistor voltage divider with the voltage impressed across the top of S. Calculate the current through the combined series resistance (S+RL). Then, multiply this current by RL to figure out the voltage across RL. Multiply the voltage across RL by the current through RL (which you just determined) to calculate the power dissipated by RL.
1D) Solve this the same way that you solved 1C. Since RS = RL in this case, this will give you the maximum power transfer. Its always the case that when the source impedance matches the load impedance that maximum power transfer occurs.

Question 2) Mesh circuit analysis is used to simultaneously solve for the currents through components connected in a circuit. Node analysis solves for voltages at the nodes that connect components. The approaches are equivalent. The answer is D.

3) False. A current source has a fixed current output. As the load attached to the current source changes, the current -remains the same-. What changes is the voltage across the load that is impressed on it by the current source. So, if you connect a current source to a large resistor or a small resistor, doesn't matter, the current through the resistors will be the same. But, less voltage will be needed to push the current through the smaller valued resistor.

Hope this helps,

-Guru

Answer 3

1) D. This is a fundamental theorem of electrical engineering.

2) D (I'm only 99% sure about this one -- could be C also)

3) True. A Norton equivalent is a current source in parallel with a resistor. If you short it out, the parallel resistor does not draw any current, because the short draws all the current.

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