Study Notes: Circuits — University Assignments

Control Document: Circuits

General Information

  • Institution: Université Sidi Mohamed Ben Abdellah de Fès
  • Faculty: Faculté des Sciences et Techniques de Fès
  • Date: 2025-2026
  • Duration: 1 hour 15 minutes

Exercise 1: Equivalent Norton Generator

Problem Description

We are provided with a circuit diagram where we need to determine the equivalent Norton generator for dipole AB using the Thévenin-Norton transformation.

Tasks

  1. Determine the equivalent Norton generator for dipole AB.
       This involves first calculating the Thévenin equivalent voltage and resistance for the dipole AB, and then converting this to its Norton equivalent.
       - Thévenin's Theorem states that any linear circuit can be replaced by an equivalent voltage source (V_th) in series with a resistance (R_th).
       - Find the short-circuit current (I_sc) to obtain the Norton current.
       - Use the relationship:
    IN=VthRthI_N = \frac{V_{th}}{R_{th}}

  2. Calculate the voltage U_AB and the current I that traverses the load R = 2KΩ.
       - Apply Ohm's Law:
    UAB=IimesRU_{AB} = I imes R
       - Given values:
         - Voltage Source = 10 V
         - Total current into the circuit = 10 mA, 5 mA, and 40 mA into various branches.

Schematic Overview
  • The circuit includes resistors and sources:
      - Resistors of 2KΩ, 1KΩ, and 3KΩ,
      - Source voltages of 10V, and various currents.

Exercise 2: Kirchhoff's Laws

Problem Description

Using the provided figures, apply Kirchhoff’s laws to determine the currents I1, I2, and I3 in the circuit shown in Figure 1.

Tasks

  1. Determine currents I1, I2, and I3 using Kirchhoff's laws, specifically:
       - Kirchhoff's Current Law (KCL): The total current entering a junction must equal the total current leaving the junction.
       - Kirchhoff's Voltage Law (KVL): The sum of electrical potential differences (voltage) around any closed network is zero.
       - Set up the equations based on the loop and node rules.

  2. Introduced Load: Now connect a dipole (E', r') to R3. Determine the current I' using the Thévenin theorem.
       - For the network with R1 = R2 = R3 = R, the effective load can be calculated using the following steps:
       - Compute the Thévenin equivalent voltage (V_th) and resistance (R_th) at the terminals of R3 when the dipole is attached.
       - Calculate the current across the dipole using:
    I′=Vth′Rth′+r′I' = \frac{V_{th}'}{R_{th}' + r'}

  3. Given Values for Calculation:
       - E = 40 V
       - E' = 10 V
       - r' = 2Ω
       - R = 24Ω
       - Use these numerical values to compute I'.
         - Substitute values into the derived equation from step 2 to find the numerical solution for I'.