The output voltage of a Flyback transformer is a function of the current retention in the transformer as the magnetic field collapses. Key considerations are leakage inductance and interwinding capacitance. Typical values for capacitance are <10pF and leakage inductance <40uH. The inductance determines the amount of time that is required for the pulse to collapse to zero. The primary winding of the flyback transformer typically has an inductor in series with the primary winding. The inductor is used to increase the current storage capacity required by the load. Current storage design parameters include leakage inductance (uH) and DCR as they define the discharging time for the inductor.