81-1 Introduction 1 Circuit models(模型) The voltage source Two active(有源) models The current source The resistor Three passive无源) models The inductor The capacitor
Ohm's law states that voltage across many types of conducting materials is directly proportional to the current flowing through the material. U= Ri or R= i R--resis tance()( linear resistor) The resistor is a passive element that cannot deliver power or store energy