《电路》（英文版）1-6 source transformations

81-6 Source transformations The ideal voltage source and a series resistance comprise a practical voltage source. RsE R --internal-resis tance R L R.+r R R L R+R A practical current source is defined as an ideal current source in parallel with an internal resistance r R.R L R+r L R Rail L R L R+R

§1-6 source transformations The ideal voltage source and a series resistance comprise a practical voltage source. R int ernal resistance s − − − s L s L R R i + =   s L s L L L L R R R R i + = =    A practical current source is defined as an ideal current source in parallel with an internal resistance Rsi. s si L si L L i R R R R +  = s si L si L L L i R R R i R + = / = RL L i − +  L − +  s Rsv RL L i − +  L s i Rsi

We shall define two sources as being equivalent if each produces identical current and identical voltage in any loads which is placed across its terminals. R Conditions of equivalence: IL R+R R+r R R R Ri Example: 34 十 6 L 2 i,=3( 1A 2+4 U=4 2+4 P=4W P=4W 3A=4(3)=12W P6v=6(1)=6w

We shall define two sources as being equivalent if each produces identical current and identical voltage in any loads which is placed across its terminals. Conditions of equivalence: s L s L R R i + =   s si L si i R R R + =  Rs = Rsi = Rs Example: i L ) 1A 2 4 2 3( = + =  L = 4V i L 1A 2 4 6 = + =  L = 4V P4=4W. P6V=6(1)=6W. P4=4W. P3A=4(3)=12W. − + 6V 2 L i − +  L 2 4 L i − +  L 4 3A s s s  = R i