Similar to the input capacitors, the output capacitors must limit the voltage ripple and support an RMS current. However, for DCM operation, the high peak secondary current results in a relatively substantial RMS current in the output capacitors, usually requiring multiple capacitors in parallel.

First, estimate the maximum ESR of the output capacitors (R_{ESR_MAX}) based on the output ripple requirement and highest secondary peak current at full load (I_{SEC_PEAK}). When an electrolytic capacitor is used, the output ripple magnitude is mainly determined by the ESR ripple. Paralleling the two output capacitors, C9 and C10, reduces the total ESR less than R_{ESR_MAX}.

Next, calculate the minimum required output capacitance to meet the output voltage ripple requirement assuming full-load and 90% of R_{ESR_MAX}

Finally, calculate the RMS current the output capacitors must withstand at full load (I_{COUT_RMS}), considering the demagnetizing time (i.e. duty cycle (D_DEMAG)) during DCM operation. Note that paralleling two or more output capacitors, C9 and C10, shares the total RMS current and also reduces the power loss contributed by the ESR.