Alternating current in a chain represents an electric stream of charged particles which direction and speed periodically changes in time under a certain law.
Instruction
1. Address the general to concept alternating current in an electrical circuit described in the school textbook. There you will see that alternating current is an electric current which value changes under the sinusoidal or cosinusoidal law. It means that current size in the alternating current main changes under the law of a sine or cosine. As a matter of fact, it answers that current that it flows in a household electrical network. However the sinusoidalnost of current is not the general definition of alternating current and not up to the end explains the nature of its course.
2. Draw the schedule of a sinusoid on the sheet of paper. According to this schedule it is visible that the value of the function expressed by current in this context changes from positive value to negative. And time through which there is a sign change, always the same. This time is called the period of fluctuations of current, and the size return at the right time – the frequency of alternating current. For example, the frequency of alternating current of household network is 50 Hz.
3. Pay attention to what is designated by function sign change physically. Actually, it means only that at some point current begins to flow in the opposite direction. And, if the law of change sinusoidal, then change of the direction of the movement happens not jump, and to gradual braking. From here both a concept of alternating current, and its main difference from constant which always flows in the same direction and has a constant. It is known that the direction of current is set by the direction of positively charged particles in a chain. Thus, in a chain of alternating current charged particles through certain time change the direction of the movement to opposite.
4. It is worth noticing that the variable value of size of current in a chain of alternating current has to mean what at connection of the ampermeter in similar network of his shooter will fluctuate here and there with a frequency of alternating current. However, as we know, it does not occur. The fact is that ampermeters of alternating current measure only average value of current during its fluctuation, but not the current value.
5. Peer at the schedule drawn with you earlier. Actually, change of the direction of the movement (sign of function) and convertibility of size of current can be set any any function, and not just a sinusoid, and such current will also be alternating. For example, one of widespread types of alternating current is current which schedule of the law looks in the form of saw edges. Such alternating current is called sawtooth.