Power supply
A power supply is an electrical device that supplies electric power to an electrical load. All power supplies have a power input connection, which receives energy in the form of electric current from a source, and one or more power output connections that deliver current to the load.
A transformerless power supply (TPS) is basically just a voltage divider that takes the 115 or 220 VAC from your wall and divides it down to whatever voltage you want. If that voltage needs to be DC, it is rectified through a few diodes, and maybe regulated to a maximum voltage but we’ll get to that in a minute.
VOUT = VIN(RO)/(RO+RS)
VOUT Is obtained by and fixed by output potential divider resistor.
