Bode Plot Analysis - Electrical - Engineer Boards
Engineer Boards

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Bode plot of capacitor of 1 Farad shows that it gives the gain of 20 dB for the frequency of 0.016 Hz, 0 dB for the frequency of 0 Hz, and gain of -20 dB for the frequency of 1.60 Hz. Gain of 20 dB refers to amplification of input voltage by 10 times. Similarly, gain of -20 dB refers to amplification of input voltage by 0.1 times whereas 0 dB gain means no gain in voltage, i.e. V out=V in.
Is this the fact? Does capacitor really gives gain? Is it possible to amplify the output voltage just by using capacitor? Can anyone please explain me the bode plot below? ##### Share on other sites

1/s is the impedance of the 1F capacitor. So, you are doing a bode plot using the impedance of the capacitor as a transfer function. That makes sense only if the output of your system is a voltage, and the input is a current (because voltage over current is impedance). In that case your plot makes sense because when you reduce the frequency, the current through the capacitor goes down (impedance of capacitor goes up when frequency goes down), therefore, the ratio between voltage and current goes up. If the frequency goes all the way to zero (DC), then the voltage/current ratio will be infinite, because no current (steady state) will flow across the capacitor.

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