TECHNOLOGY 

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KembaraXtra-Computer Science-Kirchhoff's Voltage Law (KVL)
Core Concept:
  • The sum of all voltages around any closed loop in a circuit must equal zero.
  • This is a fundamental principle for analyzing circuits.
Key Ideas:
  • Voltage Source: Supplies voltage to the circuit (positive voltage).
  • Voltage Drop: Occurs across circuit elements (like resistors) as they "use" the voltage (negative voltage).
  • Closed Loop: A complete path in a circuit that starts and ends at the same point.
How it Works:
  1. Voltage Supplied: The voltage source provides a certain voltage (e.g., 10V).
  2. Voltage Drops Across Elements: As current flows through each element (e.g., resistor), a voltage drop occurs.
  3. Sum to Zero: The sum of the voltage source (positive) and all the voltage drops (negative) around the loop must equal zero.
Example:
  • A circuit with a 10V power supply and three resistors in series (4kΩ, 6kΩ, 10kΩ).
  • Total Resistance: 4kΩ + 6kΩ + 10kΩ = 20kΩ
  • Current (I): Using Ohm's Law (V = IR), I = 10V / 20kΩ = 0.5mA.
  • Voltage Drops:
    • Across 4kΩ resistor: V = (0.5mA) * (4kΩ) = 2V
    • Across 6kΩ resistor: V = (0.5mA) * (6kΩ) = 3V
    • Across 10kΩ resistor: V = (0.5mA) * (10kΩ) = 5V
  • Voltage at Points:
    • VA = 10V (connected to the positive terminal)
    • VD = 0V (connected to the negative terminal/ground)
    • VB = VA - 2V = 8V
    • VC = VB - 3V = 5V
  • KVL Confirmation: 10V (source) - 2V (drop) - 3V (drop) - 5V (drop) = 0V
Series Resistors:
  • Resistors connected along a single path are in series.
  • The total resistance of series resistors is the sum of the individual resistances: Rtotal = R1 + R2 + R3 + ...
Ohm's Law Reminder:
  • V = IR (Voltage = Current * Resistance)
  • I = V/R (Current = Voltage / Resistance)
  • R = V/I (Resistance = Voltage / Current)
Key Takeaways:
  • KVL applies to any closed loop in a circuit, regardless of resistor values.
  • Voltage drops are considered negative voltages in the KVL equation.
  • KVL helps determine unknown voltages and currents in a circuit.



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