Opto Mosfet (SSR) equivalent circuit

[Tony Williams]

In article <d2th9q$5mf$1@reader1.imaginet.fr>,
OBones <obones_gfd_@_gfd_altern.org> wrote:

Well, I have the schematic ready, it's just that I can't find
those OptoMosfets. I may end up replacing them by a DPDT relay,
but it uses more amps, and that's not desirable (well, I could
live with it)

A relay is better at the side issues of overvoltage
and overcurrent. For reduced power use a bistable
maglatch relay, which only needs to be pulsed to
switch over. For best low level signal handling
choose a sealed relay with au-au contacts.
eg, Omron G6AK-234 series.

--
Tony Williams.

 

[OBones]

Tony Williams wrote:

In article <d2th9q$5mf$1@reader1.imaginet.fr>,
OBones <obones_gfd_@_gfd_altern.org> wrote:


Well, I have the schematic ready, it's just that I can't find
those OptoMosfets. I may end up replacing them by a DPDT relay,
but it uses more amps, and that's not desirable (well, I could
live with it)


A relay is better at the side issues of overvoltage
and overcurrent. For reduced power use a bistable
maglatch relay, which only needs to be pulsed to
switch over. For best low level signal handling
choose a sealed relay with au-au contacts.
eg, Omron G6AK-234 series.

Thanks for that.

 

[OBones]

Ross Herbert wrote:

How can you guarantee.....
By using standard techniques to minimise transient line peaks as all
other telco interfaces must do.

Yep, I know that. It's just that I feel safer using an optically
isolated device.

In order to design your own 2 line sharing device with auto selection
you are taking on what appears be a simple project but it is more
complex than you think.

Well, I have the schematic ready, it's just that I can't find those
OptoMosfets. I may end up replacing them by a DPDT relay, but it uses
more amps, and that's not desirable (well, I could live with it)

You may be better off buying an off the shelf line sharer which has
the functions you require
http://natcomm.com.au/australia/index.cfm?page=product_details&id=37&product_id=37

Yeah, I know about those devices, but it's way too expensive considering
the cost of shipping. And there is the DIY syndrom as well.

Ah well, I'll wait a bit more for the distributors here to reply to my
emails, and I'll see how it goes.

Thanks a lot for your help
Olivier

 

[OBones]

Winfield Hill wrote:

OBones wrote...

Well, I have the schematic ready, it's just that I can't find those
OptoMosfets. I may end up replacing them by a DPDT relay, but it uses
more amps, and that's not desirable (well, I could live with it)


What was wrong with my suggestion of using a low-current form B
ssr (with a series resistor) to drive a triac? This will work
for both low-voltage dc and high-voltage ampere-range ac.

The problem is not the current in the ssr (phone signals are around
60mA, way under the 100mA limit), the problem is to actually find those
ssr in electronics store around here in France.
I would prefer to use two Form C SSRs, but if I can find 1 dual Form A
and 1 dual Form B, i'd use them.
Problem is, noone seems to use this among the hobbyists...
Ah well.