Why can't current flow in this circuit?
Why Can't Current Flow In This Circuit?
Well, it can - except if the voltage waveform is a square wave. I suspect that, if you look at the text accompanying the figure you've shown, that that is exactly what is happening.
When the voltage is positive, it stays at one voltage. As a result, the capacitor never starts to discharge, as it would during the second half of a sine wave.
When the voltage goes negative, it does so &quot;infinitely fast&quot; to a negative voltage and stays there.
So, check the waveform which is supposed to be driving your circuit.