serial port powered relay.

J

Jasen Betts

Guest
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.


--
¡spuɐɥ ou 'ɐꟽ ʞooꞀ

--- news://freenews.netfront.net/ - complaints: news@netfront.net ---
 
On 2 Sep 2010 11:38:03 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

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.
Click to expand...
---
How do you unlatch it?

---
JF
 
John Fields wrote:

On 2 Sep 2010 11:38:03 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:


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.


---
How do you unlatch it?

---
JF
I think that is one of those ratchet relay's..
Click to expand...
 
In article <bb058c21-8110-456b-a8c3-d2a75057d68c@l6g2000yqb.googlegroups.com>,
George Herold <ggherold@gmail.com> wrote:
Whats the Z0107AM? The only hit I got when I googled it was your
post.
Click to expand...
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.


--
Wim Lewis <wiml@hhhh.org>, Seattle, WA, USA. PGP keyID 27F772C1
"We learn from history that we do not learn from history." -Hegel
 
On Thu, 02 Sep 2010 11:06:00 -0500, John Fields
<jfields@austininstruments.com> wrote:

On 2 Sep 2010 11:38:03 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

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.

---
How do you unlatch it?

---
JF
Click to expand...
Positive spike sets the relay, negative spike resets it. It's one of
those permanent-magnet latching types.

Cute circuit.

John
 
On 2010-09-02, Wim Lewis <wiml@underhill.hhhh.org> wrote:
In article <bb058c21-8110-456b-a8c3-d2a75057d68c@l6g2000yqb.googlegroups.com>,
George Herold <ggherold@gmail.com> wrote:
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.
Click to expand...
yes, that's the one. sorry about the bad label.



--
¡spuɐɥ ou 'ɐꟽ ʞooꞀ

--- news://freenews.netfront.net/ - complaints: news@netfront.net ---
 
On 2010-09-02, John Fields <jfields@austininstruments.com> wrote:
On 2 Sep 2010 11:38:03 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

Serial port powered relay.

DTR ----------------o----.
| |
| / 10K
100nF === \
| / RL 50 Ohms
/ | || ______
Z0107MA __|>|______o__||____| |___
| |<| || |______| |
| || |
| 100uF 16V latching |
| bipolar relay |
GND ---------o-------------------------------'

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

---
How do you unlatch it?
Click to expand...
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.





--
¡spuɐɥ ou 'ɐꟽ ʞooꞀ









--- news://freenews.netfront.net/ - complaints: news@netfront.net ---
 
On 3 Sep 2010 13:12:11 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

On 2010-09-02, John Fields <jfields@austininstruments.com> wrote:
On 2 Sep 2010 11:38:03 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

Serial port powered relay.

DTR ----------------o----.
| |
| / 10K
100nF === \
| / RL 50 Ohms
/ | || ______
Z0107MA __|>|______o__||____| |___
| |<| || |______| |
| || |
| 100uF 16V latching |
| bipolar relay |
GND ---------o-------------------------------'

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

---
How do you unlatch it?


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.
Click to expand...
---
Yes, I'd forgotten that RS-232 uses NRZ signaling, thanks.

One small nit-pick: DTR is an output.

---
JF
 
On Fri, 03 Sep 2010 09:12:29 -0500, John Fields
<jfields@austininstruments.com> wrote:
One small nit-pick: DTR is an output.
Click to expand...
---
But, in your circuit, an input, Duh!!!

---
JF
 
John Fields wrote:

But, in your circuit, an input, Duh!!!

---
JF
Click to expand...
is it not the same!? output and input? off course, there's a differency
in resistance ;-)


--
Daniel Mandic
 
On 03 Sep 2010 15:56:30 GMT, "Daniel Mandic"
<daniel_mandic@hotmail.com> wrote:

John Fields wrote:

But, in your circuit, an input, Duh!!!

---
JF

is it not the same!? output and input?
Click to expand...
---
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.
---

off course, there's a differency in resistance ;-)
Click to expand...
---
In this case, yes, but not in all cases.

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

---
JF
 
John Fields wrote:

On 03 Sep 2010 15:56:30 GMT, "Daniel Mandic"
daniel_mandic@hotmail.com> wrote:

is it not the same!? output and input?

---
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.
---

off course, there's a differency in resistance ;-)

---
In this case, yes, but not in all cases.

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

---
JF
Click to expand...
:) I can't measure in electronics with you John Fields, yet. I have
had luck...

Thanks for the link!


--
Daniel Mandic
 
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