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I am given this figure below:

https://i.stack.imgur.com/NqA51.png

And I am trying to find Vout and the gain.

From looking at this source: https://www.electronics-tutorials.ws/opamp/opamp_5.html I have determined the gain to be 10k/1k * (v+ - v-). I was just hoping for some confirmation on this answer that I got...

I also tried to find Vout, however, in doing so I neglected the 1k resistor to get: Vout = -10k * C * d/dt(Vin)

I only neglectected the 1k resistor as I am not sure how to go about finding Vout with that resistance there. Is neglecting the 1k resistor wrong?

I appreciate any help, thank you.

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  • \$\begingroup\$ Since there are no terminals labeled "v+" and "v-" in your schematic, your formula could be right or could be wrong, but there's no way for us to read your mind and figure out which terminals you think those labels refer to. \$\endgroup\$ – The Photon Apr 3 at 0:10
  • \$\begingroup\$ On some op-amps, "v+" and "v-" are the names of the power supply terminals. If that's the case for your op-amp, then the formula is almost certainly wrong. \$\endgroup\$ – The Photon Apr 3 at 0:12
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    \$\begingroup\$ This is not Differential Amplifier. This is Differentiator Amplifier, the correct link is here. Sunnyskguy already answered but I believe this paper from TI may help you learning to design real life practical differentiator circuit with op-amp. \$\endgroup\$ – Unknown123 Apr 3 at 2:35
  • \$\begingroup\$ You have a DC-blocking high-pass-filter circuit, with gain of 10x for higher frequencies. \$\endgroup\$ – analogsystemsrf Apr 3 at 3:50
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Your estimate at high f is correct Av = -Rfb/Zin(f) = -10 above f >> 1/2πRinC for Rin=1k

For this configuration the transfer function is the ratio of the Feedback Impedance to the inverting Input impedance as Vin- is a virtual ground.

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The output impedance of the signal source must be added to the 1k input resistor to calculate the gain at frequencies the capacitor and amplifier can pass.

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