Скачать или смотреть Lesson 32. Electric Current

Current is the "Flow Rate": Just like measuring how many gallons of water pass a point every second, electric current is the amount of electrical charge (electrons) passing a point in one second.
Voltage is the "Pressure": This is the force pushing the water through the pipe. Without this "push," the water (or electrons) stays still.
Resistance is the "Pipe Size": A narrow pipe or a kink in the hose makes it harder for water to flow. In electricity, materials like thin wires or specific components (resistors) act as "narrow spots" that slow down the current.
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2. How It Actually Works
Current occurs when tiny particles called electrons move through a conductor, such as a copper wire.
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The Power Source: A battery or wall outlet creates a pressure difference (voltage) that forces these electrons to move in one direction.
The Closed Path: For current to flow, there must be an uninterrupted, circular path (a closed circuit). If you flip a switch to "off," you create a gap in the path, and the current stops instantly.
Doing Work: As current flows through a device like a light bulb or a motor, the moving electrons transfer their energy to that device, turning it into light, heat, or movement.
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3. Measuring the "Intensity"
Current is measured in Amperes (or Amps, symbol A).
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1 Ampere is a specific, massive quantity of electrons—about 6.24 billion billion—moving past a point in exactly one second.
A larger number of Amps means more electricity is flowing. For context, a typical smartphone charger uses about 1–2 Amps, while a lightning bolt can carry tens of thousands.
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4. The Two Main Types
Direct Current (DC): Electrons flow in one direction only, like water through a hose. This is the type of power used by batteries and most portable electronics.
Alternating Current (AC): Electrons reverse direction back and forth many times per second. This is the more efficient way to send power over long distances, which is why it's used for your home's wall outlets