In this chapter we introduce a circuit element that is very important in circuit design, the operational amplifier.This element will be used extensively in the studies of future chapters. Here we consider its use with resistors only to perform the algebraic functions of multiplication, addition and subtraction

In the chapter, we shall define the basic active and passive circuit models, explain power conventions and determine when power is delivered and absorbed, state Ohm's law and Kirchhoff's law, determine the equivalent resistance of a passive circuit containing only resistors

Find the root of the equation(x)=0

18-4 Decomposition of a circuit into linear and nonlinear parts

《电路》（英文版）18-2 Simple nonlinear resistor circuits

1. Establish a normal tree. tree branches--Us, C(, R) cot ree(chords)-i,,(, R) 2. Assign voltage and current variables. Assign a voltage (with polarity reference) to every capacitor and a current(with arrow) to every inductor; there are the state variables. Indicate the voltage across every tree branch and the current through every link in terms of the source voltages, source currents,and the state

17-3 Loop analysis 17-4 Analysis of networks containing dependent sources

Let the initial voltages on the capacitors be represented as voltage sources in series with the capacitors and the initial currents through the inductors be represented as current sources in parallel with the inductors

Relationship between branch and loop currents

1. Augmented( incidence matrix of a directed graph nodes(N+1), branches(B)