Kirchoff law consists of two laws relating to electronic circuits.
The two laws are named after Gustav Kirchoff, who described them in 1845.
Law one deals with Current (I) within a circuit, and law two deals with Potential Difference which is also commonly known as Voltage (V).
LAW 1 – THE CURRENT LAW
The current entering any junction in a circuit (i.e a component connection point on a PCB) is equal to the current leaving that junction point.
To state this law algebraically we can state:
Before you run away screaming, I will explain how to understand the algebraic equation above.
The thing that looks like a bit like a drunken ‘E’ is called an epsilon. It means the total addition of the currents entering and existing the point in a circuit.
‘I’ is the symbol for Current
‘n’ is the total number of connections (or branches) flowing towards, or away from the particular point in the circuit (known as the node point).
LAW 2 – THE VOLTAGE LAW
The Sum of all the voltages around the loop is equal to zero.
V1+V2+V3 – V4 = 0
Where V4 is the Voltage supply.