LED Dimmer - What should be used for Switching?

[Ioannis]

Sayzer, what is the 1.27?

Ioannis

[sayzer]

I know what it is but not sure if I can explain it correctly.


May be, Alain can give a hand here and explain it in technical and understandable terms.

You considered 308VDC using full bridge rectifier (and elec-cap), right?
Have you actually measured it?

[mackrackit]

http://en.wikipedia.org/wiki/Root_mean_square

[Ioannis]

So, I insist on sqr(2), meaning x1,41 of the rms voltage.

Ioannis

[sayzer]

ok.

First, we multiply AC voltage by 0.9.
then, we multiply the result by 1.41.

There, you have the result for DC voltage.

In our case here,
we muliply 220VAC by 0.9 = 198
then we multiply 198 by 1.41 = 279VDC.

This calculation is for full bridge rectifier with an elec-cap.

[rmteo]

First, we multiply AC voltage by 0.9.

Why?? .....