What are Switch-mode Power Supplies?
Switch-mode power supplies are a lot more complicated. The 115 or 230 VAC voltage is rectified and smoothed by diodes and capacitors resulting in a high voltage DC. That DC is then converted into a safe, low voltage, high frequency voltage using a much smaller ferrite transformer and FETS or transistors. The voltage is then converted into the DC output voltage of choice by another set of diodes, capacitors and inductors. Corrections to the output voltage due to load or input changes are achieved by adjusting the pulse width of the high frequency wave form.
