the voltage Vc in the figure is always equal to
2 Relevant equations
The Attempt at a Solution
From kirchoffs law,
will Vc always equal to 9 V or it will vary?
Is that really the problem statement word for word? I suspect not because it can't easily be answered.the voltage Vc in the figure is always equal to
You are right, C.W. I misinterpreted the current source as an ammeter ...Is that really the problem statement word for word? I suspect not because it can't easily be answered.
At best you can say...
VC = 5V + 4V + whatever the voltage is across the 2A current source.
The latter term is unknown.
The current source will adjust it's voltage so that KVL holds. That depends on Vc. If the current source is an ideal current source then Vc could be anything. It could be negative or huge (eg-1,000,000V). The current source will do whatever it takes to make KVL hold. That allows Vc to be anything.
Yeah, but that IS the traditional symbol for a current source, whereas the ammeter is usually just an A in a circleNow that you mention it perhaps it is an ammeter. It would make some sense given the odd wording of the question.
If it's an ammeter it doesn't matter what's in the box, long as it results in a current of 2A:Though even if it is established that it's an ammeter, we are still left with an unanswerable question.
What's in the box? Perhaps anand raj could tell us if there is some overlooked detail that should be shared. I'm thinking the box represents a variable load. But only because if it were to represent a fixed load, the question would seem trite.
Nominating an ammeter reading of 2A seems pointless and confusing if the load is intended to be variable, though.
If it's an ammeter icon, it may not tell us the direction of the current. Besides, I see nothing here that suggests the box contains a voltage/current source of any description.If it's an ammeter it doesn't matter what's in the box, long as it results in a current of 2A:
So? No one modifies circuit icons for each instance.I could haved sworn I saw an arrow pointing from left to right.
Vc can't be just anything. Vc depends on what's inside the box.
If the circuitry in the box is represented by its Thevenin equivalent: a voltage source Vth in series with a resistance Rth, then Vc = Vth - 2*Rth.
A combination of a current source in series with a resistor and a voltage source behaves just like the current source alone. Vc won't depend on the 2Ω resistor and the 5V source; it depends only on what's in the box; not only is the 5V source irrelevant, so is the 2Ω resistor.
If nothing is in the box, just a pair of terminals hanging in the air, then Vc→∞, and Vc will be whatever it takes to sustain the arc across the terminals.
For some really kinky circuit elements, see: