Yes the circuit I attached in the previous post works 
at about 50KHz. The transformer is using a small ring
core and use solid isolation (>=1mm plastic between
the primary and secondary) to achieve reinforce (double)
insulation. Therefore the efficiency can not be very 
high (at about 70%) but it is good for normal low power
use.

Regards,
Xiaofan

-----Original Message-----
From: David Minkler [mailto:mink@luxtron.com]
Sent: Tuesday, October 04, 2005 1:32 AM
To: Microcontroller discussion list - Public.
Subject: Re: [EE] Re: : Modified sine timing?


Philip,

An RM core isn't designed for operation at 50Hz.  You probably can't get 
enough turns on the core to make it work there.  Try 50kHz, you'll have 
better luck there (and you'll need less turns).

Dave
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