Uo=1.5U1-5U2+0.1U3 = -[ -(1.5U1+0.1U3) +5U2];
取 Uo' = -(1.5U1+0.1U3),顯然是表示為壹個反相加法器電路;
則,Uo = -[ Uo' + 5U2 ];表示為另壹個反相加法器電路;
下圖是反相加法器電路,有
Uout = - Rf*(Ui1/R1+Ui2/R2);
1)第壹個加法器:
取 Uout=Uo',==》- Rf*(Ui1/R1+Ui2/R2)=?-(1.5U1+0.1U3);
Ui1=U1,Ui2=U3,則:Rf/R1=1.5,Rf/R2=0.1;取 R1=1,Rf=1.5,R2=15;
2)同理第二個加法器:
有 Uo = Uout,==》Uo = -[ Uo' + 5U2 ] =- Rf' *(Ui1' / R1' + Ui2' / R2');
取 Uo'=Ui1',那麽 Rf' = R1',Ui2' = U2',那麽 Rf' / R2' = 5,則取 Rf' = 1,R2' = 0.2;