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beginner opamp question

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alexowen

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Hi, i am very new to electrical engineering - i cannot seem to find any decent tutorials online for this type of stuff ->

**broken link removed**

just need to find a relation of v(in) to v(out)

thanks in advance,
alex. o.


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The circuit is a basic integrator. The output voltage is the integral of the input voltage:
Vout/Vin = -1/(sR1*C1)
You can see this in the time domain if you write Kirchhoff's current law at the inverting input. The input bias current of the op amp is very small (0). Recall that the current trough C1 is i_c(t)=C1*[dv_c(t)/ dt], where v_c(t) is the voltage across C1, then integrate (there is an integration constant, that is proportional to Vout(0) ).
 
I don't want to start a new thread, so I'm writing my question here (somewhat related):

I'm having problems testing an instrumentation amplifier (AD620), I've set the circuit using a Rg for a gain of 5 (I don't remember the value right now), the circuit seems to work, but the output is limited to 2 Vpp, and I don't understand why since the supply voltage is 12/-12 Vdc. Could you tell me what I'm doing wrong?
I got the input from a function generator, 1 Vpp (well, I'm changing the value to see the circuit behaviour) at 10 KHz, connected directly to the amp inputs (floating source), and the AI ref pin is connected to the supply's ground.

Thanks in advance for your help,
Geo.
 
Well, I forgot about simulation and went on testing the circuit. We finally managed to get it working, I'll try again with the simulator, but once I get some time :).

Anyway, thank you.

JJ (GeoMX).
 
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