Basic Rules of Electronic Circuits

Introduction

The following rules (known as Kirchoff's rules) hold for all circuits and are illustrated for the simple case of a battery and a resistor.

Kirchoff's current rule (junction theorem)

The current leaving a point in a circuit must equal the current entering that point. This rule is a consequence of the conservation of charge.

Kirchoff's voltage rule (loop theorem)

The sum of potential differences in a complete circuit must equal zero. This rule is a consequence of the conservation of energy.