Re: question for Mariss

Jon,

They are very nice indeed until you look at the on / off time specs,
usually 50uS to 100us.

These devices are meant for 60Hz zero-crossing applications and the
timing specs reflect that.

Back to the Schottky bridge scheme as a result.

Mariss

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Jon Elson <elson@p...> wrote:
>
>
> JanRwl@A... wrote:
>
> >In a message dated 3/23/2003 3:45:21 PM Central Standard Time,
> >mariss92705@y... writes:
> >
> >
> >
> >>Math seems OK to you?
> >>
> >>
> >>
> >
> >Thanks, Mariss, but I was unaware of Silicon diodes with only 0.3
drop, and
> >Germanium (0.2 V) seems to have fallen from favor for such low-
voltage-drop
> >purposes---or, have I just gotten SO far out of touch there is no
hope,
> >anymore!
> >
> >So, there would have to be FOUR (if TINY) diodes added for this,
or is a
> >"bridge rectifier" with only total 0.6 V. drop available, now, in
SMT
> >package????????? I guess the teens into electronics, now, are
> >unintimidated by all this TINY SMT stuff, and it IS beautiful to
behold, but
> >for us OLDE folkes, WHEW ! ! ! ! !
> >
> >
> No, there are "AC" opto-couplers that have two LEDs connected in
parallel,
> with one reversed. Therefore, one will conduct on either polarity,
and
> light
> will shine on the phototransistor. They are usually used with
circuits to
> detect the presence of some AC voltage, but can also be used to
operate off
> either polarity of DC signal. Using this type of device, there are
no extra
> diodes to add, and no voltage drop from the diodes. This is almost
> certainly
> cheaper than adding components externally.
>
> Jon