Circuit Theory #20 | Superposition Method - Current in a 12 kOhm Resistor

Instructor: Dr. Süleyman Burak ÇELİK

Twentieth lesson in the Circuit Theory series. This lesson introduces the superposition method and then applies it to a circuit with two current sources and one voltage source. The goal is to find the downward current through the 12 kOhm resistor. Main ideas: - Keep only one independent source active at a time - Replace inactive voltage sources with short circuits - Replace inactive current sources with open circuits - Keep the same reference direction for every contribution Worked example: - Contribution from the 30 mA source: `i1 = 2 mA` - Contribution from the 15 mA source: `i2 = 2 mA` - Contribution from the 15 V source: `i3 = -0.5 mA` - Total current: `i = i1 + i2 + i3 = 3.5 mA` downward Main takeaway: - Superposition does not mean adding source values directly - Each source is solved in the original circuit with the other independent sources deactivated - Negative contributions are valid; they simply oppose the chosen reference direction