11.4 Kirchhoff's Laws

• The definition of KCL is that the sum of currents entering and leaving a node is zero
• In KCL equations, currents entering the node are added
• Steps to apply KCL in circuit analysis

  1️⃣ Identify Nodes

  2️⃣ Define Current Directions

  3️⃣ Write KCL Equations

  4️⃣ Solve the Equations
• KCL states that the sum of all voltage drops around a closed loop is zero

  False
• Kirchhoff's Voltage Law focuses on the conservation of charge

  False
• What does Kirchhoff's Voltage Law (KVL) state about the sum of voltage drops around a closed loop in an electrical circuit?

  Must be zero
• Match the definition with the correct law:

  Kirchhoff's Voltage Law (KVL) ↔️ Sum of voltage drops around a closed loop is zero

  Kirchhoff's Current Law (KCL) ↔️ Sum of currents entering/leaving a node is zero
• Steps to apply KVL in solving circuit problems:

  1️⃣ Identify Closed Loops

  2️⃣ Assign Voltage Polarities

  3️⃣ Write KVL Equations

  4️⃣ Solve the KVL Equations
• KVL equations can be solved using Ohm's Law to find unknown voltages or currents.


  True
• In a series circuit with a 12V battery, a 4Ω resistor, and a 6Ω resistor, what is the current I?

  1A
• In KVL, the sum of all voltage drops around a closed loop must equal zero.


  True
• In KCL, the primary focus is the conservation of charge.
• Steps to apply KCL to solve circuit problems

  1️⃣ Identify nodes

  2️⃣ Define current directions

  3️⃣ Write KCL equations

  4️⃣ Solve the equations
• Steps to apply KVL to a series circuit

  1️⃣ Identify the closed loop

  2️⃣ Assign voltage polarities

  3️⃣ Write the KVL equation

  4️⃣ Solve using Ohm's Law
• KVL states that the sum of voltage drops around a closed loop is zero
• Steps to apply Kirchhoff's Voltage Law (KVL) to solve circuit problems

  1️⃣ Identify Closed Loops

  2️⃣ Assign Voltage Polarities

  3️⃣ Write KVL Equations

  4️⃣ Solve the KVL Equations
• What does the KVL equation state for a closed loop in a circuit?

  Sum of voltage drops is zero
• In the practice problem, the KVL equation for Loop 1 is 10V - 5Ω * I1
• What is the value of I1 in the example circuit?

  2A
• The voltage drop across R1 is calculated as 5Ω * 2A = 10V
• According to KCL, the sum of currents entering and leaving a node is zero
• Kirchhoff's Current Law focuses on the conservation of energy

  False
• Ohm's Law is often used with KCL to solve circuit problems


  True
• What does Kirchhoff's Current Law ensure in an electrical circuit?

  Charge conservation
• What does Kirchhoff's Voltage Law (KVL) state about the sum of voltage drops in a closed loop?

  Sum must be zero
• What is the focus of Kirchhoff's Voltage Law in circuit analysis?

  Energy conservation
• Kirchhoff's Voltage Law (KVL) states that the sum of all voltage drops around a closed loop in an electrical circuit must be zero
• KVL focuses on the conservation of charge, while KCL focuses on the conservation of energy.

  False
• When applying KVL, assign voltage polarities based on the assumed current direction
• In a series circuit with a 12V battery and two resistors, what is the KVL equation?

  12V - 4I - 6I = 0
• Match the step in applying KVL with its action:

  Identify Closed Loops ↔️ Locate all closed circuits in the network

  Assign Voltage Polarities ↔️ Determine the positive and negative terminals of each voltage drop
• Steps to apply KVL to a simple series circuit

  1️⃣ Identify the closed loop

  2️⃣ Assign voltage polarities

  3️⃣ Write the KVL equation

  4️⃣ Solve using Ohm's Law
• Match the focus of KCL and KVL with their descriptions:

  KCL ↔️ Conservation of charge at a node

  KVL ↔️ Conservation of energy around a loop
• Kirchhoff's Voltage Law (KVL) states that the sum of all voltage drops around a closed loop in an electrical circuit must be zero.
• KCL focuses on the conservation of charge at a node, while KVL focuses on the conservation of energy around a loop.
• What is the primary focus of KVL in electrical circuits?

  Conservation of energy
• In a simple series circuit with a 12V battery, a 4Ω resistor, and a 6Ω resistor, what is the KVL equation?

  12V - V_4Ω - V_6Ω = 0
• Combining KCL and KVL allows for the complete analysis of complex electrical circuits.


  True
• What does the KCL equation at Node A state in the example circuit?

  I1 = I2 + I3
• In the example circuit, I2 is equal to 1.5 * I3

  True