What is "DC"? Amps in one direction only? If those amps change in magnitude only, is it not DC?
For clarity, "amps" is a vector.

The wiki's are ok.
Some confusing words in there. The simplest RL ckt is a coil all by itself, because a coil is itself also a resistor (Rdc). Where in the Wiki equations does it account for the Rdc of the coil itself?

It explains the RL ckt using two components for analysis, namely R and pure inductor L.
In reality, an inductor has it's own R. What does that analysis look like when the ckt is R1 resistor, R2 of coil wire, and pure L , when R2 is of significant value, like R1=R2=200ohms (small wire lots of turns).

In other words, with just a coil (L & R) you cannot measure VR and VL separately when viewing it as a voltage divider.

Sorry, current is not a vector it is a scalar.

You can apportion the resistance any way you like and it changes neither the circuit not the analysis, because resistances in series can be added together, and more importantly after steady state is achieved the current is the same in all parts of a series circuit. The part where things are changing is called the transient analysis because that is the transition from one steady state to another.

One more thing. The analysis is the same regardless of which direction you assume for the current. You can consider voltage drops to be positive or negative. Whichever one you choose a voltage source must go the opposite way.

 

Sorry, current is not a vector it is a scalar

C/s (amp, J/V s) bound by physical properties of the conducting metal, amps is a vector (C/s and direction).
If C/s (amp) does not have a direction for any given time, how could you define the magnetic field in-full? If we dont know amp direction then we can only calculate magnitude of mag field, but could not define position of the poles.

C/s alone tells us some net charge passing through a defined 2D area (flux density), would have direction.

 

C/s (amp) bound by physical properties of the conducting metal, amps is a vector (C/s and direction).
If C/s (amp) does not have a direction for any given time, how could you define the magnetic field in-full? If we dont know amp direction then we can only calculate magnitude of mag field, but could not define position of the poles.

Electric current is a scalar quantity. Any physical quantity is defined as a vector quantity when the quantity has both magnitude and direction but there are some other factors which show that electric current is a scalar quantity . When two currents meet at a point the resultant current will be an algebraic sum. In scalar quantities, normal rules of algebra are applicable while in vector quantities different sets of rules are applicable. That’s why we can say that electric current is a scalar quantity.

 

Electric current is a scalar quantity. Any physical quantity is defined as a vector quantity when the quantity has both magnitude and direction but there are some other factors which show that electric current is a scalar quantity . When two currents meet at a point the resultant current will be an algebraic sum. In scalar quantities, normal rules of algebra are applicable while in vector quantities different sets of rules are applicable. That’s why we can say that electric current is a scalar quantity.

I read that too (https://www.vedantu.com/question-an...lass-11-physics-cbse-5fcf071715a78672d18f2818).

Can C/s meet and flow through a point, at the same time?

 

Quite an interesting discussion here. And I am wondering about the actual implementation of the solenoid. That is because there are some applications where the solenoid is used as a liner-motion servo actuator, working against both a load and a spring. One very interesting application was a speed control for a diesel engine, which used a solenoid with a PWM driver to adjust the injection pump delivery. As the engine load varied the fuel deliver had to vary to hold a constant RPM, and so the solenoid drive had to be adjusted. So the position, and inductance, were constantly changing, and as a result the radiated EMI kept changing, as the solenoid was a fairly high force device, drawing quite a few amps.
A discussion with the controller manufacturer disclosed that the analysis was "terribly complex" and so they simply designed the driver system to withstand "much more than they expected" in the way of voltage, current, and total power.
Hydraulic servo valves have a similar situation, the choice there sems to have been to stay with linear current control and avoid using PWM . At least that was the last I got from one large hydraulics company.

 

Good conversation all around.

Back to C/s being a vector or not. Scalar math is nothing more than a special case of vector math. It's not unlike a square being a special rectangle. Squares are rectangles. "square" is just an adjective which describes a special rectangle.

Scalar addition or subtraction is nothing more than special cases of vector sum math, where one vector is exactly 180deg (1 pi radians) from the other, or one vector is exactly 0deg (0 pi radians) from the other.

If we look at amps in terms of C/s through some defined area of 2D plane in 3D space, charge can flow across (through) that area at some rate (call that C/s). If some charge goes across that area at 1C/s (left) and some other charge goes across that area at 2C/s (right), the net C/s is the vector sum of the two (two vectors 180deg from each other) = 1C/s (right). This boils down to the simpler scalar math. The angle at which charge crosses that 2D plane area in 3D space reduces down to charge crossing perpendicular to that plane (angle makes no diff, what matters is charge rate C/s crossing that area).

So, I think you can apply vector math for all things electrical. I also believe that "amps" is a net vector for any area in space at any given time. Knowing the direction of C/s (amps) is required to define what the associated mag field looks like.

For me, amps is a vector.