On 3/30/2009 5:01 AM David spake thus:

Following up on my own post, the circuit is poor for other
reasons. Think about what happens on the negative half
cycles of the AC input. You need at least a 'catch' diode in
there.

OK, I take your previous point about having a bleeder resistor to
discharge the cap.

I fail to understand why "negative half cycles of the AC input" are any
kind of a problem. Isn't that the very function of a rectifier? The
1N4001, f'rinstance, is rated at 600 PIV, so what's the problem? The
negative half cycles are simply blocked by the diode, right?

Just out of curiosity, what's a "catch diode"?


--
Made From Pears: Pretty good chance that the product is at least
mostly pears.
Made With Pears: Pretty good chance that pears will be detectable in
the product.
Contains Pears: One pear seed per multiple tons of product.

(with apologies to Dorothy L. Sayers)