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1、2.2 Ohms LawDefinitionOhms law states that the voltage v across a resistor is directly proportional to the current i flowing through the resistor.Mathematical expressionResistance RThe resistance R of an element denotes its ability to resist the flow of electric current;It is measured in ohms()2.2 O
2、hms LawShort circuitA short circuit is a circuit element with resistance approaching.Open circuitAn open circuit is a circuit element with resistance approaching infinity.2.2 Ohms LawResistorfixed ResistorVariable Resistor2.2 Ohms LawLiner ResistorObey Ohms law.nonlinear resistorDoes NOT obey Ohms l
3、aw.2.2 Ohms LawConductanceConductance is the ability of an element to conduct electric current;it is measured in mhos()or siemens(S),and denoted by G:2.2 Ohms LawThe power dissipated by a resistor:1.The power dissipated in a resistor is a nonlinear function of either current or voltage.2.Since R and G are positive quantities,the power dissipated in a resistor is always positive.Thus,a resistor always absorbs power from the circuit.This confirms the idea that a resistor is a passive element,incapable of generating energy.2.2 Ohms Law2.2 Ohms Law2.2 Ohms Law