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2 votes

Should I use an op-amp buffer so I'm not affecting the original source's current requirements?

The circuit you show will attempt to short the input to ground to the extent the op-amp and associated supplies will allow it so it's less than ideal from the viewpoint of leaving the inputs ...
Spehro Pefhany's user avatar
0 votes

Shark fin output for circuit using opamps

You state that Vin is AC (capacitively) coupled, so the DC voltage for the inverting input is undefined. Set the DC value of the inverting input by a DC value (ground is a choice) through a ...
JkingNH's user avatar
  • 134
2 votes

"Inverting op-amp" circuit calculations using the general feedback formula

Yes, the non-inverting configuration is easier to put into the standard closed loop form. $$A_{?}(s)=\frac{V_{o}(s)}{U_{i}(s)}=\frac{A_{OL}(s)}{1+A_{OL}(s)\beta(s)}\tag{Equ 1}$$ So: Include a finite ...
RussellH's user avatar
  • 15k
0 votes

"Inverting op-amp" circuit calculations using the general feedback formula

Using this image from here: - You've already done the hard work. Now you just find an expression for the voltage at the inverting input and equate it to zero (knowing that the op-amp gain can be ...
Andy aka's user avatar
  • 457k
4 votes
Accepted

"Inverting op-amp" circuit calculations using the general feedback formula

For an inverting amplifier you must consider the fact that the input signal to be amplified does NOT directly arrive at the opamp inputs. Therefore, in your block diagram there must be an additional ...
LvW's user avatar
  • 26.8k
3 votes

How can I find Thévenin equivalent circuit of the NFB op-amp input?

Beyond formal explanations The answer is obvious: Looking at the op-amp input in a circuit with negative feedback you see zero resistance. It will probably do you a good job. But in addition, we have ...
Circuit fantasist's user avatar
1 vote

How can I find Thévenin equivalent circuit of the NFB op-amp input?

The op-amp circuit connected to (E,F) is incomplete although the rest of the circuit is implied as is usually the case for op-amps. Here though what is implicit must be made clear. For the Thevenin ...
RussellH's user avatar
  • 15k
0 votes

How can I find Thévenin equivalent circuit of the NFB op-amp input?

Thévenin equivalent for this is wanted. Here's some help. Start by noticing that F is op-amp input, it's NOT the ground. To make the Thévenin equivalent concept meaningful the circuit should be ...
arnold8a's user avatar
  • 141
3 votes

How can I find Thévenin equivalent circuit of the NFB op-amp input?

That's a nasty question. The trick is to realise that node E is a virtual Earth, always 0V, maintained by the right-hand op-amp itself. Assuming that op-amp is ideal, the Thevenin equivalent between E ...
Simon Fitch's user avatar
  • 35.1k
0 votes

Using an op-amp to drive LEDs according to an incoming signal

Basic idea The idea on which this particular circuit is based is much more general. It is so universal that it can be seen in non-electric form all around us. We ourselves frequently use this remedy ...
Circuit fantasist's user avatar
3 votes

Using an op-amp to drive LEDs according to an incoming signal

Here's the schematic with some helpful labels: simulate this circuit – Schematic created using CircuitLab With negative feedback, an op-amp adjusts its output to equalise the potentials \$V_Q\$ ...
Simon Fitch's user avatar
  • 35.1k

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