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Derivation of Voltage Gain in 1st order Active Low Pass Filter

JayJoe

Jul 31, 2015
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Hi, I am still new to electronics

Can anyone show me the derivation of the voltage gain shown in this photo? I know how to derive the Vout but for Vin, I have no idea.

Please help. Thank you.
 

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Harald Kapp

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for Vin, I have no idea.
You don't derive Vin, Vin is the given input.
Split the task into 3 sections:
  1. Evaluate Vc/Vin = f(R3, C1), a simple 1st order low pass filter.
  2. Evaluate Vout/Vc=f(R2,R1).
  3. Evaluate Vout/Vin = Vout/Vc * Vc/Vin
 
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