Experiment 4 - Junctions and Loops in a Circuit

Circuits can be more complicated than in the circuits from the last experiments. They can have multiple branches...

Before you examine branched circuits and Kirchhoff's laws, you need to be clear about some terms used...

• At a junction at least three current paths meet.
• A branch is the path that connects two junctions.
• A loop is a closed path of a least two paths connecting at least two junctions.

Junction.

Branch.

Loop.

Circuit of a branched circuit. (Enlarge)

In the circuit shown you have introduced two junctions A and B. All three resistors heat now up (Resistor R1 heats up much more than the other two resistors.). Therefore, at the junction the current is divided and flows through both resistors R2 and R3! Circuit diagram branched circuit. The conduct of the current at the junction is described by the first Kirchhoff law...