Learn these transformerless power supply circuits, use a capacitor instead, it smaller and lighter than transformer. There are circuits as follows.
If you are looking for 5-volts DC regulator without transformer. This circuit may help you. It is suitable for low current digital. Use the MOSFET is based.
This is Simple monitor turn on delay circuit, by use contact of relay acts as a switch. When entering an AC main to this circuit. The circuit will delay while Reduce the surge current protection with fuse.