A charged capacitor blocks steady DC
The mistake
Treating a capacitor as a wire after a long time in a DC circuit.
Why it feels right
At first current flows while charge moves, so it seems the path remains conducting.
How to catch it
You assign a nonzero steady current through a capacitor in a DC circuit.
The first principle
After a long time, an ideal capacitor in DC is fully charged and no current flows through its branch. Initially it can act like a short; at steady state it acts like an open circuit.
worked mini-example
A capacitor and resistor are connected to a battery for a long time. What is capacitor current?
Common wrong move
V/R forever.
Correct
Zero at steady state.
Test the repair CIR-07 · transfer
Make a fresh prediction before referring to the worked example.