Series - Parallel Circuits ENTC 210: Circuit Analysis I Rohit Singhal Lecturer Texas A&M University

Definition Series – Parallel circuits are networks that contain both series and parallel circuit configurations.

General Approach for Solving Take a moment, before you start calculating.  The answer may be a lot simpler than reducing everything.  There may be many “time” and “energy” saving shortcuts to solve the problem. Examine each region independently, before tying them together.

Reduce and Return Approach Applicable to all single source circuits.

Currents in Loops (Remember KCL?)

i1i1

i1i1 i2i2

i1i1 i3i3 i2i2

Ladder Networks

There are 2 approaches to solve this circuit  Reduce Resistances using series parallel analysis  Calculate current using current loops

Ladder Networks Reduce Resistances??  That’s easy!!!

Ladder Networks Calculate current using current loops  Once you have the current through the source, you know the effective resistance  Let’s do it!!!

No - Load When is “no load” observed?  When R 2 is infinitely large?  Or when R 2 is zero? R1R1 R2R2

No - Load When is “no load” observed?  When R 2 is infinitely large?  Or when R 2 is zero? When R 2 is infinite!!! R1R1 R2R2

Voltage Divider Supply What should I do if I want multiple voltage outputs from the same 9V battery?

Voltage Divider Supply R1R1 R2R2 R3R3 V3V3 V2V2 V1V1

What’s the value of V1, V2 and V3? 9V = V 1 > V 2 > V 3 R1R1 R2R2 R3R3 V3V3 V2V2 V1V1

Voltage Divider Supply We cannot calculate V 2 and V 3 unless we know what load is connected to them The less the load, the closer they are to 9V. R1R1 R2R2 R3R3 V3V3 V2V2 V1V1