> I've wondered, if the SMPS circuit in the 5W apple adapters be scaled up to 600~800W would they be enormous and/or less efficient? Because it seems like the c

> I've wondered, if the SMPS circuit in the 5W apple adapters be scaled up to 600~800W would they be enormous and/or less efficient? Because it seems like the circuits in this board are either designed for higher power so big honkin' coils & caps are necessary, or are they that big (and inefficient) in order to save money? All power supplies of a few hundred watts will look broadly the same as this one. The rare exceptions are very expensive AC/DC modules[0], and linear power supplies used mostly in higher-end audio and test equipment. There are a number of factors that influence the designs that are practical for different power outputs but a big one is the gate charge of the switching transistor. Bigger output power requires a bigger switching transistor which stores more charge in its gate. This requires more energy from the controller to charge and discharge the gate and more concern about the ohmic losses in the transistor as its transitioning from being on to being off. This limits the switching frequency you can practically use. Lower switching frequency means larger transformer; you need more iron to take the magnetic field so it doesn't saturate on the larger slower pulses. Note also that with more power almost every component needs to be larger. Also note that standard PC supplies need to supply many voltage rails while the classic Apple 5W adapter only needs one. With newer standards like ATX12VO the supply only supplies 12V and 12V standby. [0]: http://www.vicorpower.com/ac-dc/converters/ac-front-end-module http://www.vicorpower.com/ac-dc/converters/ac-front-end-modu... [1]: https://audiobacon.net/2018/06/29/linear-power-supplies-for-audiophiles-getting-closer-to-live/ https://audiobacon.net/2018/06/29/linear-power-supplies-for-...