The question of what is the power of electric current is not the easiest. To be absolutely precise, it is very difficult. But this is one of the basic concepts of both physics and other scientific disciplines related to electricity. In everyday life, we also often have to use this concept.
Without going into a detailed explanation of what an electric current is and what its nature is, we will use the analogy of a stream to understand the processes associated with it. Water flows from a higher section down. For an electric current, the situation is approximately the same; it flows from a point with a high potential to a point with a low potential. The value of the potential difference is called voltage, is indicated by the letter U and is measured in units called volts.
Let's go back to the creek. When water flows from a height to a lowland, a certain amount is transferred from one place to another. When current flows, approximately the same thing happens: a certain amount of electricity is transferred from one place to another. To measure this process, there is the term current strength , it is defined as the amount of electricity that has passed per unit time through the conductor cross section. By analogy with a stream, this means how much water passed through the selected area per unit of time. The current strength is indicated by the symbol I, for its measurement there is a special unit - amperes.
These two concepts - electrical voltage and current strength - act as the main characteristics of electric current.
Water flowing from top to bottom carries with it a certain energy. Getting, for example, on the turbine blades, it will cause the rotation of the latter and do a certain job. In the same way, electric current can do the job. This work, performed in one second, is the power of electric current. It is customary to designate it with the letter P, and it is measured in watts.
The work performed by the water in the fall is determined by its quantity falling on the turbine blades, and the height with which it falls. The more water and the greater the height with which it falls, the more work is done. In the same way, the greater the voltage (height difference for water) and current strength (i.e. the amount of water), the greater the work performed and, therefore, the power of the electric current.
If you try to formalize this concept, then everything can be expressed with a simple formula:
P = I * U,
where: P is the electric current power, in watts;
I - current strength, in amperes;
U is the voltage in volts.
This is the main formula by which the power of an electric current can be determined.
However, an electric current does not flow somewhere in abstract conditions, but in real circuits, which have their own characteristics. In particular, the conductor has a resistance, and the voltage U and the current strength I are interconnected in a circuit where a direct current flows through the resistance according to Ohm's law. So the power in the DC circuit, if necessary, can be expressed through resistance, or take into account the characteristics of the circuit in the expression for power through current and voltage, connected by Ohm's law.
Due to the fact that the circuit has resistance, not all energy is used to perform useful work. Part of it is lost when passing through the chain. Therefore, the incoming energy, i.e. the power of the energy source must be greater than the power necessary to perform a certain work. The so-called energy balance must be fulfilled - the power supplied by the source must be equal to the power of the consumed load and the power lost in the electric current conductor.
About this way you can get a general idea of what the power of an electric current is, how it is determined, on which it depends.