Aug 13, 2015 #1 Y yemi11 Newbie level 4 Joined Jun 7, 2015 Messages 6 Helped 0 Reputation 0 Reaction score 0 Trophy points 1 Activity points 61 All sources writes the kirchoffs current law for the node between Rf and Ri (in picture) and and writes a relation between equations for opamp. that results in -Rf/Ri But what actually opamp amplifies and multiply with 200000 or whatever ? if Noninverting input is zero. Than, A*(0-Vinverting)=Voutput (A, open loop gain..) What is Vinterting ? Last edited by a moderator: Aug 13, 2015
All sources writes the kirchoffs current law for the node between Rf and Ri (in picture) and and writes a relation between equations for opamp. that results in -Rf/Ri But what actually opamp amplifies and multiply with 200000 or whatever ? if Noninverting input is zero. Than, A*(0-Vinverting)=Voutput (A, open loop gain..) What is Vinterting ?
Aug 13, 2015 #2 LvW Advanced Member level 6 Joined May 7, 2008 Messages 5,915 Helped 1,754 Reputation 3,514 Reaction score 1,366 Trophy points 1,393 Location Germany Activity points 40,529 The voltage at the inv. node Vn can be calculated using all the classical formulas: Superposition: * Vn1=f(Vin) for Vout=0 * Vn2=f(Vout) for Vin=0 * Vn=Vn1+Vn2=-Vout/Ao
The voltage at the inv. node Vn can be calculated using all the classical formulas: Superposition: * Vn1=f(Vin) for Vout=0 * Vn2=f(Vout) for Vin=0 * Vn=Vn1+Vn2=-Vout/Ao