Look at TB008 from Mocrochip's web page.  They describe a transformerless
power supply derived from 110VAC.  The circuit can be easily changed to work
from 230VAC.  Note that this type of supply is only good for currents around
20mA, after that the series capacitor gets to be too large.  I have used
this type of supply to power a PIC with good results.  If the current draw
is very low, a resistor can be used in place of the 1uF capacitor (in my
application the capacitor took up too much space).

This supply is NOT isolated from the mains.  Care should be taken to protect
the user from touching any part of the circuit (even 5V) in case of a fault.

Alan
-----Original Message-----
From: Seth Fischer <aureo@xtra.co.nz>
To: PICLIST@MITVMA.MIT.EDU <PICLIST@MITVMA.MIT.EDU>
Date: Saturday, October 03, 1998 6:56 PM
Subject: 230VAC->5Vdc without transformer


>I would like to build a a 5V d.c. power supply for a PIC derived from
>the mains supply of 230V A.C. with out using a transformer.
>
>Currently my only idea is to use a couple of 5W ceramic resistors in
>series across the mains supply as a voltage divider and use this to
>supply a bridge rectifier / three terminal regulator circuit.
>
>Is there a better or more efficient way of obtaining 5V d.c. with a
>small compact circuit?
>
>
>Seth Fischer
>