3/26 10.1 Bridge Circuit ◆Wheatstone Bridge Applications:strain gage,resistance thermometer,or thermistor. Vac= R1 ）Eex(10.1) R1+R4R2+R3 Vac =0 when =2 R4 R3' Eer fR=R+AR and△R《R,(Interol m A AA resistance △R2Eex(10.2) Vac=R+R neglected R "Meter i+im 12-Im ◆Error Analysis D Fig.10.1 Basic Wheatstone Bridge 426 10.2 Amplifiers Operational Amplifiers Instrumentation Amplifiers Difference/Differential Amplifiers Programmable Gain Amplifier /Variable Gain Amplifier Transconductance and Transimpedance Amplifiers Noise Problems,Shielding,and Grounding ◆Others Charge Amplifiers and Impedance Converter Logarithmic Amplifier ●Multiplier/Divider10.1 Bridge Circuit Fig.10.1 Basic Wheatstone Bridge ‹Wheatstone Bridge ‹Applications: strain gage, resistance thermometer, or thermistor. ܸ௔௖ = ோభ ோభାோర − ோమ ோమାோయ ܧ௘௫ … (10.1) ܸ௔௖ = 0 when ோభ ோర ோమ ோయ ; If ܴଵ ᇱ = ܴଵ + ∆ܴଵ and ∆ܴଵ ≪ ܴଵ, ܸ௔௖ = ∆ோభ ோభାோర ܧ௘௫ …(10.2) ‹Error Analysis 3/26 10.2 Amplifiers ‹ Operational Amplifiers ‹ Instrumentation Amplifiers ‹ Difference/Differential Amplifiers ‹ Programmable Gain Amplifier / Variable Gain Amplifier ‹ Transconductance and Transimpedance Amplifiers ‹ Noise Problems, Shielding, and Grounding ‹ Others z Charge Amplifiers and Impedance Converter z Logarithmic Amplifier z Multiplier/Divider 4/26