The conventional choice of lagging vs leading angle to represent the phase difference between voltage and current in AC circuits is somewhat arbitrary.
The standard convention of a lagging current (or leading voltage) likely arose from the historical analysis of resistive-inductive circuits, where current naturally lags the voltage.
However, for a capacitive circuit, the current leads the voltage. There is no inherent reason why we must adhere to the historical convention of having current lag voltage in all cases. An alternative convention could just as well designate current leading voltage for inductive circuits and lagging for capacitive circuits. While this alternative is not commonly used, it was firstly introduced by Steinmetz by 1900 in its book "THEORY AND CALCULATION ALTERNATING CURRENT PHENOMENA" [1], page 21, but then it was neglected in favour of the current interpretation. To me, it sounds more natural the Steinmetz interpretation for several reasons.
What do you think?
[1] http://www.survivorlibrary.com/library/theory_and_calculation_of_alternating_current_phenomena_1900.pdf.
You are NOT RIGHT. If we consider an inductor, which is practically an inductor connected in series with a resistor, we first have to apply a voltage, and after that (with a time delay) the current appears. Consider for example a voltage step, and the current will increase linear in time after applying the voltage.
So it is very intuitive to consider as time reference the moment when you apply the voltage, and the current will follow the voltage
Dear Remus Vladimir,
I'm sorry but you must be confused. Your answer has absolutely nothing to do in this discussion.
i am not so sure that you are right
you CAN NOT have current without voltage; but you you CAN have voltage without current, so it is more logical to consider voltage as reference
Interesting discussion.
I absolutely support the opinion of Remus Vladimir Vladimir Ghincu regarding voltage, current and transients. This opinion is also relevant in principle in the case of steady sinusoidal processes.
However, I took a closer look. And yes. Question to figure 10a and commentary to it. With the specified direction of rotation on the figure, the comments do not join.
On the other hand, it's also not clear! Why is there a phase shift with a "minus" sign in the time function (b). And the angle AOB has already been taken with the "plus" sign... and the situation is opposite with the function (c).
At the same time, a certain skepticism arose in me, only in terms of instantaneous power. But having studied many works, I can safely say that most of the disagreements (especially in the orthogonal power components) are due to the original function of the harmonic current or/and voltage, which the author lays down. Sine or cosine. And the transition to vectors is actually done using the Euler transform.
Sinusoidal waveforms of the same frequency can have a Phase Difference between themselves which represents the angular difference of the two sinusoidal waveforms. Also the terms “lead” and “lag” as well as “in-phase” and “out-of-phase” are commonly used to indicate the relationship of one sinusoidal waveform to another. The generalised sinusoidal expression given as: A(t) = Am sin(ωt ± Φ) represents the sinusoid in the time-domain form.
But when presented mathematically in this way it can sometimes be difficult to visualise the angular or phasor difference between the two (or more) sinusoidal waveforms. One way to overcome this problem is to represent the sinusoids graphically within the spacial or phasor-domain form by using Phasor Diagrams, and this is achieved by the rotating vector method
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