§7-5 The phasor(相量) A sinusoidal current or voltage at a given frequency is characterized by only two parameters, an amplitude and a phase angle. The complex representation of the voltage or current is also characterized by these same two parameters i=Im cos(at +p)Imei(at+p) the current response: i= cos(ar+q)=√2Icos(a+q)→√2lel(a+) i=v2/ cos(at+o) ∠q D=√2 V cos ot→>∠0° A time representation A frequency domain(i*) representation The phasor: V∠00I=I∠q§ 7-5 The phasor（相量） A sinusoidal current or voltage at a given frequency is characterized by only two parameters, an amplitude and a phase angle. The complex representation of the voltage or current is also characterized by these same two parameters. ( ) cos( )     → + = + j t i I m t I me the current response: ( ) cos( ) 2 cos( ) 2       → + = + = + j t i I m t I t Ie i = 2I cos(t +) → I   = 2V cost →V0 A time representation A frequency domain(频域) representation The phasor:   =  =  • • V V 0 I I