(b)求内阻R;20 492 5 加压求流 6 69 R1→ 6Q b 29 a 5U1+8I0+U1=U7 5U1 U1=21 0 0 R=U0/l0=20 b 2QRi (b) 求内阻Ri 加压求流 5U1+8I0+U1=U0 U1=2I0 Ri=U0 /I0=20 a b 2 4 6 6 6 5U1 + – – U1 + 2 4 4 5U1 a b U0 I0 + – – U1 + + –