Kirchoff's current law question

AI Thread Summary
The discussion revolves around the application of Kirchhoff's current law in the context of a band pass filter circuit involving a capacitor and resistor in parallel. The original poster is confused about the direction of current through the capacitor, believing it should be calculated as the input current minus the current through the resistor. However, the derivation suggests the opposite, indicating that the current through the capacitor is the resistor's current minus the input current. This discrepancy is attributed to the standardization of current direction, which can follow either the passive sign convention or the conventional current flow. Ultimately, the equation Ic + Ir = I holds true, leading to the conclusion that Ic = I - Ir.
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I'm looking at the derivation of a band pass filter circuit, and part of the circuit is a capacitor and resistor in parallel from the non-inverting input to the output. My thinking is that the current through the capacitor is going to be the current coming in (since the inverting input draws no current) minus the current going through the resistor, or Ic = I - Ir. Nope, the derivation has it the other way, Ic = Ir - I. I can't figure out why this is.
 
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depends on the standardization of current. If current is defined as direction holes travel in, than it follows passive sign convention whereas, current is usually defined as direction opposite of electron flow. I see your point. Ic + Ir = I so
Ic = I - Ir...
 
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