s3.2.1IR调理电桥电路 dE E R 4 E OR (R+R4) R3 aR R2+R) aE R2 B OR3"(R2+R) ac=-E R OR (R1+R) R R2 aE aE △E≈-△R1+c△R,+ a AR oe ac △R OR OR ORA Eac= eab+ ebc= eab -ech R- RE R1+R4R2+R3 Ec 1+/ROmR,R/R2+R)+RR/(R+R)11 §3.2.1 IR调理——电桥电路 3 2 4 1 R R R R = C R1 R4 R2 R3 R0m A B D E Eac 4 4 3 3 2 2 1 1 R R E R R E R R E R R E E a c a c a c a c a c     +    +    +     E R R R R R R Eac Eab Ebc Eab Ecb         + − + = = + = − 2 3 2 1 4 1 ( ) ( ) ( ) 1 1 0 2 3 2 3 1 4 1 4 1 E R R R R R R R R R E a c m acL + + + + = ( ) 2 1 4 4 1 R R R E R Eac + =   ( ) 2 1 4 1 4 R R R E R Eac + = −   ( ) 2 2 3 2 3 R R R E R Eac + =   ( ) 2 2 3 3 2 R R R E R Eac + = −  