Electric current is the ordered movement of electric charges (such as electrons or ions) in a conducting material, created and maintained by an electric field. Electric current is a fundamental phenomenon of electricity, which is crucial to modern technology and energy use.
How is electric current created?
- Electric voltage: An electric current requires a voltage difference (potential difference) to occur, which generates an electric field. This voltage forces charge carriers (such as electrons) to move in a specific direction.
- Conducting material: For current to flow, a material is needed in which charge carriers can move easily. Examples of such materials are copper, aluminum, or ions in electrolytes.
- Charge carriers: Electric current is produced by the movement of charged particles (such as electrons or ions). In metals, current is produced by the movement of electrons, while in liquids or gases, ions can also conduct current.
Direction of current
- Direction of positive charges: The direction of current is defined as the direction of movement of positive charge carriers, even though the current is actually created by the opposite movement of electrons (negative charges)
- Direct current (DC) : The direction of the current is constant, such as in batteries or solar panels .
- Alternating current (AC) : The direction of current changes periodically, as we see in electrical networks. For example, according to the European standard, the frequency of AC is 50 Hz, which means that the direction changes 50 times per second.
Types of electric current
| Type | Characteristic | Example |
|---|---|---|
| Direct current (DC) | The direction of the current is constant. | Batteries, solar panels |
| Alternating current (AC) | The direction of the current changes periodically. | Electrical network, household appliances |
Units of measurement for electric current
Current (I):
The amount of electric current is determined by current strength, which measures how much charge passes through the cross-section of a conductor in a given time.
Its unit of measurement is ampere (A).
Formula: I = Q / t
Q: charge (coulomb, C)
t: time (seconds, s)
Voltage (U):
The potential difference created by an electric field that moves charges.
Its unit of measurement is volts (V).
Resistance (R):
The property of a conducting material that impedes the flow of current.
Its unit of measurement is ohm (Ω).
Ohm's law:
Describes the relationship between current, voltage and resistance: I = U / R
Safety information regarding electricity
- Dangerous current: Even a few tenths of an ampere can be dangerous to the human body, especially at high voltage.
- Grounding: Grounding electrical equipment protects the user from electric shock.
- Fuses and circuit breakers: These devices prevent overcurrent and fires.
Summary
Electric current is the ordered movement of electric charges that is the basis for energy use and the operation of electronic devices. The different properties of direct current and alternating current enable different applications, from generating energy in solar panels to operating household appliances. In order to use electric current safely and efficiently, it is essential to know the basic physical laws and safety rules.