V battery to an 
resistor. The difference is that we chose to measure the voltages and currents in the two circuits differently: we used a different coordinate system of voltages and currents in our measurements.
You are to determine the voltages and currents indicated and compute the powers entering the elements.
After watching the lecture videos S2V3 and S2V4, it is clear that I've been using a convention exactly opposite to Professor Agarwal. Because it doesn't matter, and because I'm not "set in my ways", I think I'll abandon my previous conventions and just follow what Professor Agarwal does.
After watching the lecture videos S2V3 and S2V4, it is clear that I've been using a convention exactly opposite to Professor Agarwal. Because it doesn't matter, and because I'm not "set in my ways", I think I'll abandon my previous conventions and just follow what Professor Agarwal does.
Voltage conventions:
- Travel around the loop in either direction, but the sign of the term will always be the first symbol (+ or -) encountered.
Current conventions:
- Currents leaving the node result in a positive term, currents entering the node result in a negative term.
Again, the convention chosen doesn't really matter; I'm just choosing this one to stay consistent with the learning material that I am attempting to absorb.
What is the voltage (in Volts)
measured across the battery?
The voltage across v1 is defined as 6 Volts.
What is the voltage (in Volts) 
measured across the resistor?
measured across the resistor?
The voltage across v2 must also be 6 Volts.
What is the current (in Amperes) 
measured entering the battery?
measured entering the battery?
V = IR
I = V / R
I = 6 / 18 = 1 / 3 = -0.33 Amps
What is the current (in Amperes) measured entering the resistor?
measured entering the resistor?
0.33 Amps
What is the power (in Watts) 
entering the voltage source?
entering the voltage source?
P1 = 6 * (-1/3) = -2 Watts
What is the power (in Watts) entering the resistor?
What is the voltage (in Volts) 
measured across the battery?
entering the resistor?
P2 = -P1 = 6 * (1/3) = 2 Watts
measured across the battery?
-6 Volts
What is the voltage (in Volts) 
measured across the resistor?
measured across the resistor?
-6 Volts
What is the current (in Amperes) measured entering the battery?
measured entering the battery?
0.33 Amps
What is the current (in Amperes) measured entering the resistor?
measured entering the resistor?
-0.33 Amps
What is the power (in Watts) entering the voltage source?
entering the voltage source?
-2 Watts
What is the power (in Watts) entering the resistor?
2 Watts
Notice that the powers are the same in the two circuits. That is physical reality: power moves from the battery to the resistor, independent of the coordinate systems we use to measure the voltage and the current, so long as we use associated reference directions. We must always measure current into the terminal that we put the + sign of the voltage measurement on. Think of this as the red probe of the voltmeter.
entering the resistor? 2 Watts
Notice that the powers are the same in the two circuits. That is physical reality: power moves from the battery to the resistor, independent of the coordinate systems we use to measure the voltage and the current, so long as we use associated reference directions. We must always measure current into the terminal that we put the + sign of the voltage measurement on. Think of this as the red probe of the voltmeter.
Thanks a million for the clarification! Omg
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