Circuit Theory #21 | Superposition with a Dependent Source - Find Vx

Instructor: Dr. Süleyman Burak ÇELİK

Twenty-first lesson in the Circuit Theory series. This lesson applies superposition to a circuit that includes a dependent voltage source. The goal is to find Vx, the voltage across the 15 ohm resistor. Main idea: - Superposition still works for linear circuits with dependent sources - Only independent sources are deactivated - A dependent source stays active in every subcircuit - In each contribution, the dependent source follows that contribution variable Worked example: - Contribution from the 75 V source: `Vx1 = 15 V` - Contribution from the 5 A source: `Vx2 = -30 V` - Contribution from the 150 V source: `Vx3 = 90 V` - Total voltage: `Vx = Vx1 + Vx2 + Vx3 = 75 V` Main takeaway: - Do not turn off dependent sources during superposition - Keep the reference polarity fixed from the beginning - Negative contributions simply mean the source opposes the chosen polarity