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serial port powered relay.

J

Jasen Betts

Jan 1, 1970
0
Serial port powered relay.

DTR ----------------o----.
| |
| / 10K
100nF === \
| / RL 50 Ohms
/ | || ______
Z0107AM __|>|______o__||____| |___
| |<| || |______| |
| || |
| 100uF 16V latching |
| bipolar relay |
GND ---------o-------------------------------'


I just threw it toogether and it worked, i'm not sure if the
values chosen are optimum.


I was able to commutate a 25A 250VAC rated relay
with a 7.5V, 50 ohm coil

the only down sidea are you need to wait 10s for the
capacitor to charge before it'll switch and the
slightly oddball parts.
 
W

Wim Lewis

Jan 1, 1970
0
Whats the Z0107AM? The only hit I got when I googled it was your
post.

Looks to be a small triac from Philips/NXP. The -AM is the package suffix,
maybe just a typo for Z0107MA, which is a SOT54 aka TO92 package.
 
J

Jamie

Jan 1, 1970
0
I think that is one of those ratchet relay's..
 
J

Jasen Betts

Jan 1, 1970
0
Looks to be a small triac from Philips/NXP. The -AM is the package suffix,
maybe just a typo for Z0107MA, which is a SOT54 aka TO92 package.

yes, that's the one. sorry about the bad label.
 
J

Jasen Betts

Jan 1, 1970
0
Set the oposite voltage on the input.

PC serial port has a high resistance (about 1K2) and an open circuit voltage of
about +/- 11v

So if you model the input labeled DTR as a slow bipolar 11V square wave
through a 1K2 resistor you'oull see that the circuit works by charging
the big capacitor through the 10K resistor and then discharging it in
a surge through the triac when the input changes polarity.

Then you have to wait for it to charge up again.





--
¡spuÉÉ¥ ou 'Éꟽ ÊžooꞀ









--- news://freenews.netfront.net/ - complaints: [email protected] ---
 
D

Daniel Mandic

Jan 1, 1970
0
John said:
But, in your circuit, an input, Duh!!!

is it not the same!? output and input? off course, there's a differency
in resistance ;-)
 
D

Daniel Mandic

Jan 1, 1970
0
John said:
On 03 Sep 2010 15:56:30 GMT, "Daniel Mandic"


---
It is not the same; an "output" drives, while an "input" is driven.

I read Jasen's post in the context of DTE when I should have been
reading it in the context of DCE.

:) I can't measure in electronics with you John Fields, yet. I have
had luck...

Thanks for the link!
 
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