Resistors control current flow by providing opposition (resistance) to the movement of electric charge (electrons) in a circuit.
⚙️ How Resistors Work
- A resistor is made from a material that resists the flow of electrons (often carbon, metal film, or wire).
- This resistance limits the amount of current that can pass through it.
📏 Key Principle: Ohm’s Law
V=I×R
Where:
- V = Voltage (volts)
- I = Current (amperes)
- R = Resistance (ohms, Ω)
This tells us:
- More resistance (R) → less current (I) for the same voltage.
- Less resistance → more current.
🧠 Simple Analogy
- Think of current as water flowing through a pipe, and the resistor as a narrow section of the pipe:
- A wide pipe (low resistance) = more water flows.
- A narrow pipe (high resistance) = less water flows.
🔧 Main Functions of Resistors
- Function Description
- Current limiting Protects components like LEDs or transistors by reducing current
- Voltage division Splits voltage in a circuit (voltage divider circuits)
- Heat dissipation Converts excess electrical energy into heat
- Biasing components Sets correct operating conditions for transistors or amplifiers
- Pull-up/pull-down Stabilizes inputs in digital circuits (prevents floating voltages)
➡️ You’d place a 350-ohm resistor in series with the LED to limit the current and prevent it from burning out.
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