Output capacitor in buck converter
For future use, use Q = C * V (charge = capacitance times voltage).
If you take the derivative with respect to time, you get

dQ/dT = C * dV/dT + V * dC/dT

If we define dQ/dT = current (I), and define dC/dT = ZERO, we now have

dQ/dT = I = C * dV/dT

Now let us use that for ripple of 0.01 volt, for 1microSecond delay time, with 1 amp load:

I = C * dV/dT ===&gt;&gt; C = I * dT/dV

and we substitute

C = 1 amp * 1uSecond / 0.01 volt = 1uF/0.01 = 100 microfarad

Notice this does not bring up the Resonance of the Inductor with this Capacitor which affects the SwitchReg regulation_loop (negative feedback) stability and phase margin.
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Read the comment by &quot;BobT&quot; for appropriate caution on Capacitor ESR.