Build a relais card for the lpt with Solid-State-Relais

M

Maik Wiege

Guest
Hello!
I want to build me a relais card for my printer port. I found an nice cicuit
at dicsolitez:
http://discolitez.com/circuits-32deluxe.shtml
To make it mor simple I want to replace the MOC's and Triacs with
solid-state-relais. Here is what I think how it should look:
http://www.einnettesdesign.de/schaltung.gif

Because my knowledge in electronics is not that good, I wanted to check it
first and hope you all can give me a good responce for this.
I think perhaps the resistance as to be bigger, because in the dicolitez
circuit there was something said, that the relais has to work with 5V, but
the one I found uses lesser voltage.

The datasheets of the D-Latch and the relais can be found here:
http://ece-www.colorado.edu/~mcclurel/dm74ls374.pdf
http://wulfman.com/pdffiles/s202s02.pdf

Thanks for any help
Maik Wiege
 
Maik Wiege wrote:
Hello!
I want to build me a relais card for my printer port. I found an nice cicuit
at dicsolitez:
http://discolitez.com/circuits-32deluxe.shtml
To make it mor simple I want to replace the MOC's and Triacs with
solid-state-relais. Here is what I think how it should look:
http://www.einnettesdesign.de/schaltung.gif

Maik Wiege
------------------------------
Click to expand...
But the MOCs and TRIACs *ARE* Solid State Relays!!!!!!!

-Steve
--
-Steve Walz rstevew@armory.com ftp://ftp.armory.com/pub/user/rstevew
Electronics Site!! 1000's of Files and Dirs!! With Schematics Galore!!
http://www.armory.com/~rstevew or http://www.armory.com/~rstevew/Public
 
"Maik Wiege" <miggedy*noSpam*@gmx.de> schreef in bericht
news:c44oo8$dvi$00$3@news.t-online.com...
Hello!
I want to build me a relais card for my printer port. I found an nice
cicuit
at dicsolitez:
http://discolitez.com/circuits-32deluxe.shtml
To make it mor simple I want to replace the MOC's and Triacs with
solid-state-relais. Here is what I think how it should look:
http://www.einnettesdesign.de/schaltung.gif

Because my knowledge in electronics is not that good, I wanted to check it
first and hope you all can give me a good responce for this.
I think perhaps the resistance as to be bigger, because in the dicolitez
circuit there was something said, that the relais has to work with 5V, but
the one I found uses lesser voltage.

The datasheets of the D-Latch and the relais can be found here:
http://ece-www.colorado.edu/~mcclurel/dm74ls374.pdf
http://wulfman.com/pdffiles/s202s02.pdf

Thanks for any help
Maik Wiege
Click to expand...
Maik,

You're on the right way but there's one thing wrong. From the SSRs
datasheet you can learn that the component requires at least 5mA to trigger,
from your LS374 datasheet you can learn that an LS374 can provide only
2.6mA. But... the LS374 can sink up to 24mA. So you have to connect the SSRs
input and current limiting resistor between Vcc and the LS374 output. `The
only point is, the SSR is on when the LS374 output is low. You can deal with
that either in the software or by using inverting buffers between the
printer port and the LS374s.

petrus


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In the schematic, what is the purpose of the triac that is being triggered.
 
Kevin Weddle wrote:
In the schematic, what is the purpose of the triac that is being triggered.
Click to expand...
Refer to the schematic. The triac, when triggered,
connects the "Mains Live" line to the left side of
the load (L in the red circle).
 
The only thing I notice is that the photodetector can handle the mains
voltage. I know that the photodetector is used in many low voltage
situations. Since the the photodector handles high voltage, the photo
transmitter must have a lot of current. You don't want the triac to
trigger only to have it untrigger.
 
"Kevin Weddle" <kevinweddle@yahoo.com> schreef in bericht
news:31ac621b.0403291026.280fa33d@posting.google.com...
The only thing I notice is that the photodetector can handle the mains
voltage. I know that the photodetector is used in many low voltage
situations. Since the the photodector handles high voltage, the photo
transmitter must have a lot of current. You don't want the triac to
trigger only to have it untrigger.
Click to expand...
Kevin,

Don't understand this post. The S202S02 mentioned is an SSR. (Solid State
Relay.) Its input is a phototransmitter (LED) circuit but who cares? The
point is that it requires 6-20mA to turn the relay on and the 74LS374 is not
able to provide hat current. The photodetector itself does not handle the
high voltage. That job is done by another part of the circuit, a TRIAC. But
again, who cares? Point is you can switch 230VAC devices on and off with it.
Of course the TRIAC inside the SSR must be triggered to switch the load on.
And if you want to switch it off, you have to remove the input current. The
concept of "untriggering" a TRIAC is unknown. At least to me.

petrus


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Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.639 / Virus Database: 408 - Release Date: 22-3-2004
 
I read in sci.electronics.design that petrus bitbyter <p.kralt@reducespa
mforchello.nl> wrote (in <xblac.48117$s9.4615@amsnews02.chello.com>)
about 'Build a relais card for the lpt with Solid-State-Relais', on Tue,
30 Mar 2004:
The
concept of "untriggering" a TRIAC is unknown. At least to me.
Click to expand...
If you don't provide the triac with enough trigger current, the main
current may be confined to just part of the die area, which can overheat
and fail. The main current then stops and the triac is permanently
damaged.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
 
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