Opamp feedback question

Tweakers' Asylum

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After going through the LM 3875 application notes and reviewing some basic circuit theory, the open loop gain of the theoretical op amp is infinite as the voltage on the + and - inputs are the same. However, in a real world situation, the LM 3875 has an open loop gain of around 100 dB. If the closed loop gain (with feedback) is 30 dB, then does that mean that the negative feedback is 70 db?

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Kimber Kable

Topic - Opamp feedback question - bilbobaggins 18:53:18 03/15/03 (3)

Re: Opamp feedback question - Steve Eddy 22:54:23 03/15/03 (2)

Re: Opamp feedback question - bilbobaggins 05:51:49 03/16/03 (1)

Re: Opamp feedback question - Steve Eddy 09:35:27 03/16/03 (0)

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