Build a wide input, wide output switched power supply preregulator
Benchtop power supplies with power transformers are heavy and expensive, especially when designed to supply a few hundred watts. Furthermore, such designs are old school. Today, using switch-mode configurations it is possible to design 250-watt PSUs running from anything from 85 up to 265 VAC line voltage, yet weigh less than 500 grams. The design showcased here is even open source.