[Solved] Understanding Phase in Alternating Current: Simple Explanation & Its Role in Sinusoidal Waves

Hello.
I have a question, what is phase in alternating current? (I mean such a simple phase that is presented at the beginning of learning alternating current)
The term "phase" is portrayed in books and on websites, but nowhere is it explained what it actually is. On some English site I found the statement that "A phase is a given point in time in a sinusoidal wave" and nothing else. Maybe someone will explain to me or confirm whether this statement is true.

Thank you in advance

Alternating current from the English alternating current, AC a characteristic case of periodically alternating current in which the instantaneous values are subject to changes in a repetitive, periodic manner, with a specific frequency, e.g. 50 times per second, our current in Polish sockets.

Hello,
https://pl.wikipedia.org/wiki/Faza_fali
that is, to simplify it, it is the shift of the wave in relation to its beginning.
Regards

So it can be said that it is the distance from the initial phase (t = 0)?

Phase - has several concepts in electricity.
The first and most important thing is something a la source. In order for the current to flow from this source, a so-called neutral conductor is needed, now called neutral.

All over the world, power generators are three-phase, that is, they generate electricity in three separate "sources". These "sources" are out of phase (the latter term) by an angle of 120 °.
There must be a potential difference for the current to flow. Such a difference is between a given source (given phase) and the neutral wire (in Poland it is 230 V), or between two sources (phases) (in Poland 400 V).

The concept of phase is very difficult for a beginner to understand, but with time it will become bread and butter.
You have certainly seen a single-phase plug, i.e. two pins, phase and neutral. Maybe you saw or maybe not the three-phase plug. Currently, it has 5 pins, 3 of them are phases (each is shifted by 120 ° in relation to the other), the fourth is neutral and the fifth is protective.

You have such a simplified drawing


What my colleague SuhaK01 described below is the third phase concept, the so-called initial phase.

Trzcinkan wrote:

So we can say that it is the distance from the initial phase (t = 0)?

Regarding the concept of phase understood as a phase shift:

The initial phase is the distance from t = 0.

For example, when a sine wave "starts" at t = 0, the start phase is zero. However, if we shift this course to the left or right (in relation to the coordinate system), the initial phase will be the distance from the beginning of this shifted course to the coordinate system (i.e. time t = 0). Of course, the phase is given in degrees, and it ranges from 0 ° to 360 °.
As you have probably seen, the general formula for a sinusoidal voltage waveform is: $$u(ωt) = U_{max}sin(ωt + φ)$$ where ? is your phase which shifts the waveform with respect to the origin of the coordinate system.

So from what I understand the phase is shortly called a phase shift? So then in this slide, phase angle = phase shift = phase?

"Phase" as a term used by "Mr. Mietek" is a voltage sine wave.
The second phase is also a voltage sine wave, but shifted by 120 degrees from the first.
The third one is similar, but shifted from the first by 240 degrees, and from the second by 120 degrees.

That is why Mr. Mietek has "three phases". Because each one against the neutral wire will shock him, and each one will shock him in relation to a different phase.

Phase voltage - a variety of "phase" understood more by electricians, it is the effective value of the voltage between the selected phase conductor ("phase") and the neutral conductor or the star point.

In electricity, a phase shift is not considered to be "phase".

And so it's less complicated how to say? Instead of a phase

But I don't mean any three-phase system, but what is a phase, because I don't know which answer is right anymore

Yes, for peasant reason. Phase is what it kicks.

Well, explaining to myself, it will be difficult to understand what I have to learn

Trzcinkan wrote:

But I don't mean any three-phase system, but what is a phase

I don't mean what my friend is about.

Phase is derived from power. The power supply is, as a rule, three-phase.
Phase, as I wrote before, is a voltage sine wave. There can be one, there can be three, six, twelve, as many as you like.
Phase, colloquially, is the supply voltage on one line with respect to the neutral point.

Okay, so the phase is a voltage sine wave otherwise, and it can also be a current sine wave because there is current and voltage in the phase shift?

Trzcinkan wrote:

and it can also be a sine wave of current because there is intensity and voltage in the phase shift?

This is either we use simple definitions for understanding or we go "deeper".

When we speak of "current in phase" or "out of phase" we are already talking about shifts. So the angle between voltage and current.
Generally speaking, the term "phase current" is used, but it is the current flowing in a conductor in which the "phase" occurs.

Oh, the phase is a voltage sine wave and that's enough for me, thanks