# Chapter 3. Circuit Analysis Techniques

The circuit analysis problems at the end of the previous chapter involved application of circuit laws KVL, KCL, and Ohm’s law to reduce variable unknowns and arrive at a solution. It is not always obvious which laws to use, and when, and a certain degree of trial and error is needed to arrive at a solution. This is the nature of engineering problems:  a combination of experience, judgement, method, and a willingness to engage in some  trial and error are the means to problem solving. Chapter 3 of this book deals with some organized methods for circuit analysis. We examine several different approaches, or strategies, that can lead to a simplification of a circuit and a reduction in the number of unknown variables that need to be dealt with. We examine:

• techniques for replacing networks of resistors with a single equivalent resistor (series and parallel equivalent resistance)
• techniques for determining the fractional voltage associated with a resistor network (voltage divider) and the fractional current associated with a resistor network (current divider)
• a technique for replacing a network comprised of resistors and sources with a single ideal source and a resistor (Thévenin equivalence)
• an organized technique for determining the voltage and current at any point in a circuit based on first solving for a set of node voltages (Node voltage analysis)
• a technique for determining the response of a circuit to multiple independent sources based on a linear combination of the responses to the individual sources acting individually (superposition). [TO BE ADDED]

Studying the techniques and practicing the problems should lead to greater insight and understanding about electronics and circuits. The aim in presenting these methods is to provide an introduction to the techniques, while keeping in mind that this treatment is for non-ECE majors.  For many students, this may be their first, and only electronics course in their undergraduate career, while some students might opt to undertake further study in electronics and circuit analysis as a means to learn more about robotics, biomedical instrumentation or some other field where electronics is salient. Either scenario is to the good, and the point here is to provide exposure and a degree of comfort with the material.