In article <32A85C12.10AE@whidbey.com>,
Paul Mathews <optoeng@whidbey.com> wrote:

>I don't hesitate to design without transformer isolation.  Many of my
>products use series capacitor power supplies, and any mention of this
>always brings out dozens of responses of the "You're crazy if you don't
>use a transformer!" variety.  I take comfort in the simple fact that the
>vast majority of electrical products in the world don't use a
>transformer.  However, it is too true that knowledge and care are
>essential.  Electricity can kill.  I use isolation transformers, battery
>operated scopes, differential probes, etc.  Take care.

Could you start me off on the practical design of a series capacitor supply?
I've got a 2 channel sequencer using a 16C84 which uses a resistor-zener
supply from the 120V, 120V through a resistor for zero crossing and two
triacs driven directly from PIC pins.  However, the current required by
PIC and triac drive means that the resistor has to be low enough that it
gets somewhat warm.  I can see the idea of using a capacitor there but
don't know where to start in terms of cap. value or type etc.

Thanks.