P额=U额²/R
R1:R2=P2额:P1额=2:5
1)串联电路中U1:U2=R1:R2=2:5
U1=(2/7)U P1=U1²/R1=(4/49)*P1额=400/49=8.16W
U2=(5/7)U P2=U2²/R1=(25/49)*P2额=20.41W
2)并联电路,电压减半,功率变为原来的1/4(P与U²成正比)
P1=25W
P2=10W
P额=U额²/R
R1:R2=P2额:P1额=2:5
1)串联电路中U1:U2=R1:R2=2:5
U1=(2/7)U P1=U1²/R1=(4/49)*P1额=400/49=8.16W
U2=(5/7)U P2=U2²/R1=(25/49)*P2额=20.41W
2)并联电路,电压减半,功率变为原来的1/4(P与U²成正比)
P1=25W
P2=10W