【问答题】
<p> 如图所示为电桥电路,已知R<sub>1</sub>=1Ω、R<sub>2</sub>=2Ω、R<sub>3</sub>=2Ω、R<sub>4</sub>=4Ω、R<sub>5</sub>=5Ω,试求等效电阻R<sub>ab</sub>。<br /> <img src="https://img.ppkao.com/2018-05/tangxueping/2018051015543465216.jpg" /></p>
A、如图所示为电桥电路,已知R1=1Ω、R2=2Ω、R3=2Ω、R4=4Ω、R5=5Ω,试求等效电阻Rab。