Key Stage 5
Meaning
Kirchoff's 1st Law states that the total current entering a junction is equal to the total current leaving the junction.
About Kirchhoff's First Law
- Also known as the current law or junction rule.
- Kirchoff's 1st Law is based on the conservation of charge.
- Kirchoff's 1st Law is essential for analyzing complex electrical circuits.
- In Kirchoff's 1st Law the algebraic sum of currents at a junction is equal to zero.
- Kirchoff's 1st Law helps in solving circuit problems by setting up equations based on current conservation.
- Kirchoff's 1st Law is used in network analysis techniques such as mesh analysis and nodal analysis.
- Kirchoff's 1st Law applies to both DC and AC circuits.
Formula
\(\sum I_n=I_1 + I_2 + I_3 +...=0\)
\(\sum I_{in}=\sum I_{out}\)
Where\[\sum I_n\] represents the sum of all currents at junction,
\(I_1 + I_2 + I_3 +...\) represents the current in each individual wire attached to the junction,
\(\sum I_{in}\) represents the sum of all currents going into a junction,
\(\sum I_{out}\) represents the sum of all currents leaving a junction
Examples
- In a parallel circuit, the sum of currents through each branch equals the total current entering the junction.
- Used to determine unknown currents in electrical network problems.