rc timer circuit help

Guest
Hi
I have a GSM controller that can switch a relay for a minimum time of 1 sec, however I need a 300ms pulse. I am looking for a circuit that can take the 1 sec relay output (as an input) and give me a 300ms output for a second relay.
Thanks for any help.
 
On Wed, 10 Jul 2013 00:49:32 -0700 (PDT), keithbc86@gmail.com
wrote:

Hi

I have a GSM controller that can switch a relay for a
minimum time of 1 sec, however I need a 300ms pulse. I am
looking for a circuit that can take the 1 sec relay output
(as an input) and give me a 300ms output for a second relay.

Thanks for any help.
Click to expand...
Does the 300ms start at the beginning of the 1s output
duration or at the end of it? In any case, have you looked at
the 74121 (various families), 74HC221, or 74HC123 to use
together with an external BJT or MOSFET switch?

Jon
 
On 2013-07-10, keithbc86@gmail.com <keithbc86@gmail.com> wrote:
Hi
I have a GSM controller that can switch a relay for a minimum time of 1 sec, however I need a 300ms pulse.
Click to expand...
how precise do you need to be?

--
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--- news://freenews.netfront.net/ - complaints: news@netfront.net ---
 
On Wednesday, 10 July 2013 09:49:32 UTC+2, keit...@gmail.com wrote:
Hi

I have a GSM controller that can switch a relay for a minimum time of 1 sec, however I need a 300ms pulse. I am looking for a circuit that can take the 1 sec relay output (as an input) and give me a 300ms output for a second relay.

Thanks for any help.
Click to expand...
Hi

Does not need to be that precise but should be below 500ms.
 
On Wed, 10 Jul 2013 06:57:48 -0700 (PDT), keithbc86@gmail.com wrote:

On Wednesday, 10 July 2013 09:49:32 UTC+2, keit...@gmail.com wrote:
Hi

I have a GSM controller that can switch a relay for a minimum time of 1 sec, however I need a 300ms pulse. I am looking for a circuit that can take the 1 sec relay output (as an input) and give me a 300ms output for a second relay.

Thanks for any help.

Hi

Does not need to be that precise but should be below 500ms.
Click to expand...
You could use the first relay to dump a capacitor into the coil of the second
relay. You'd have to tweak the C value a bit to get the timing right, as you'd
be working against the dropout voltage of the second relay.

One cap, one resistor.


--

John Larkin Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators
 
On Wed, 10 Jul 2013 00:49:32 -0700 (PDT), keithbc86@gmail.com wrote:

Hi
I have a GSM controller that can switch a relay for a minimum time of 1 sec, however I need a 300ms pulse. I am looking for a circuit that can take the 1 sec relay output (as an input) and give me a 300ms output for a second relay.
Thanks for any help.
Click to expand...
---
Is the output from the controller a set of relay contacts? An open
collector? A one second voltage pulse?

--
JF
 
On Wednesday, 10 July 2013 09:49:32 UTC+2, keit...@gmail.com wrote:
Hi

I have a GSM controller that can switch a relay for a minimum time of 1 sec, however I need a 300ms pulse. I am looking for a circuit that can take the 1 sec relay output (as an input) and give me a 300ms output for a second relay.

Thanks for any help.
Click to expand...
The out put is a dry contact relay.
 
On Thursday, July 11, 2013 9:08:02 AM UTC-4, keit...@gmail.com wrote:
I have a GSM controller that can switch a relay for a minimum time of 1 sec, however I need a 300ms pulse. I am looking for a circuit that can take the 1 sec relay output (as an input) and give me a 300ms output for a second relay.
Click to expand...
If this were a system with DC power supply, and logic-level output, it's easy. If it's
an AC-power (mains) system, things get trickier: the best might be an AC timed relay
connected in series, that turns OFF after 300 msec, and resets when power is
removed.

It matters a lot what kind of power is available (and what the nature of the intended
load is).
 
On Wednesday, 10 July 2013 09:49:32 UTC+2, keit...@gmail.com wrote:
Hi

I have a GSM controller that can switch a relay for a minimum time of 1 sec, however I need a 300ms pulse. I am looking for a circuit that can take the 1 sec relay output (as an input) and give me a 300ms output for a second relay.

Thanks for any help.
Click to expand...
Thanks all, going with the capacitor, resistor suggested by John, simple and effective.
 
On Thu, 11 Jul 2013 23:29:33 -0700 (PDT), keithbc86@gmail.com wrote:

On Wednesday, 10 July 2013 09:49:32 UTC+2, keit...@gmail.com wrote:
Hi

I have a GSM controller that can switch a relay for a minimum time of 1 sec, however I need a 300ms pulse. I am looking for a circuit that can take the 1 sec relay output (as an input) and give me a 300ms output for a second relay.

Thanks for any help.

Thanks all, going with the capacitor, resistor suggested by John, simple and effective.
Click to expand...
Just to be clear, the resistor is in the OFF cap recharge path, to
avoid contact wear. In the ON state, the cap is switched directly to
the second relay coil.

Entire dial telephone systems were done with relays. Computers, too.


--

John Larkin Highland Technology, Inc

jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser drivers and controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro acquisition and simulation
 
John Larkin wrote:
On Thu, 11 Jul 2013 23:29:33 -0700 (PDT), keithbc86@gmail.com wrote:

On Wednesday, 10 July 2013 09:49:32 UTC+2, keit...@gmail.com wrote:
Hi

I have a GSM controller that can switch a relay for a minimum time of 1 sec, however I need a 300ms pulse. I am looking for a circuit that can take the 1 sec relay output (as an input) and give me a 300ms output for a second relay.

Thanks for any help.

Thanks all, going with the capacitor, resistor suggested by John, simple and effective.

Just to be clear, the resistor is in the OFF cap recharge path, to
avoid contact wear. In the ON state, the cap is switched directly to
the second relay coil.

Entire dial telephone systems were done with relays. Computers, too.
Click to expand...

They also wasted a lot of power, were very slow and required a lot of
maintenance. The Strowager Stepper Switchs used in telephone exchanges
were motorized switches, not relays. There were relays, but the routing
was done with switches.
 
On Mon, 15 Jul 2013 23:26:56 -0400, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:

John Larkin wrote:

On Thu, 11 Jul 2013 23:29:33 -0700 (PDT), keithbc86@gmail.com wrote:

On Wednesday, 10 July 2013 09:49:32 UTC+2, keit...@gmail.com wrote:
Hi

I have a GSM controller that can switch a relay for a minimum time of 1 sec, however I need a 300ms pulse. I am looking for a circuit that can take the 1 sec relay output (as an input) and give me a 300ms output for a second relay.

Thanks for any help.

Thanks all, going with the capacitor, resistor suggested by John, simple and effective.

Just to be clear, the resistor is in the OFF cap recharge path, to
avoid contact wear. In the ON state, the cap is switched directly to
the second relay coil.

Entire dial telephone systems were done with relays. Computers, too.


They also wasted a lot of power, were very slow and required a lot of
maintenance. The Strowager Stepper Switchs used in telephone exchanges
were motorized switches, not relays. There were relays, but the routing
was done with switches.
Click to expand...
Strowgers (no 'a') are often referred to as "relays" or "rotary
relays" or "stepping relays." They work like relays and sound like
relays, so I call them relays.

We could argue about "motorized" too, since there is a relay coil or
two but no motor.


--

John Larkin Highland Technology, Inc

jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser drivers and controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro acquisition and simulation
 
John Larkin wrote:
On Mon, 15 Jul 2013 23:26:56 -0400, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:


John Larkin wrote:

On Thu, 11 Jul 2013 23:29:33 -0700 (PDT), keithbc86@gmail.com wrote:

On Wednesday, 10 July 2013 09:49:32 UTC+2, keit...@gmail.com wrote:
Hi

I have a GSM controller that can switch a relay for a minimum time of 1 sec, however I need a 300ms pulse. I am looking for a circuit that can take the 1 sec relay output (as an input) and give me a 300ms output for a second relay.

Thanks for any help.

Thanks all, going with the capacitor, resistor suggested by John, simple and effective.

Just to be clear, the resistor is in the OFF cap recharge path, to
avoid contact wear. In the ON state, the cap is switched directly to
the second relay coil.

Entire dial telephone systems were done with relays. Computers, too.


They also wasted a lot of power, were very slow and required a lot of
maintenance. The Strowager Stepper Switchs used in telephone exchanges
were motorized switches, not relays. There were relays, but the routing
was done with switches.

Strowgers (no 'a') are often referred to as "relays" or "rotary
relays" or "stepping relays." They work like relays and sound like
relays, so I call them relays.

We could argue about "motorized" too, since there is a relay coil or
two but no motor.
Click to expand...

They are referred to a an 'Electromechanical Switch' You appear to
be the only one who calls them a relay. Who ever heard of a multi-axis
relay?

--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.
 
John Larkin wrote:
We could argue about "motorized" too, since there is a relay coil or
two but no motor.
Click to expand...

For anyone who's interested, here is a link to a 40 GB torrent of
"Bell Systems Technical Journals".


<http://thepiratebay.sx/torrent/5946997/Bell_Systems_Technical_Journals_%28Full_Site_Rip%29>

They are also available online, one journal at a time.


--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.
 
On Wed, 17 Jul 2013 19:42:41 -0400, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:

John Larkin wrote:

On Mon, 15 Jul 2013 23:26:56 -0400, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:


John Larkin wrote:

On Thu, 11 Jul 2013 23:29:33 -0700 (PDT), keithbc86@gmail.com wrote:

On Wednesday, 10 July 2013 09:49:32 UTC+2, keit...@gmail.com wrote:
Hi

I have a GSM controller that can switch a relay for a minimum time of 1 sec, however I need a 300ms pulse. I am looking for a circuit that can take the 1 sec relay output (as an input) and give me a 300ms output for a second relay.

Thanks for any help.

Thanks all, going with the capacitor, resistor suggested by John, simple and effective.

Just to be clear, the resistor is in the OFF cap recharge path, to
avoid contact wear. In the ON state, the cap is switched directly to
the second relay coil.

Entire dial telephone systems were done with relays. Computers, too.


They also wasted a lot of power, were very slow and required a lot of
maintenance. The Strowager Stepper Switchs used in telephone exchanges
were motorized switches, not relays. There were relays, but the routing
was done with switches.

Strowgers (no 'a') are often referred to as "relays" or "rotary
relays" or "stepping relays." They work like relays and sound like
relays, so I call them relays.

We could argue about "motorized" too, since there is a relay coil or
two but no motor.


They are referred to a an 'Electromechanical Switch' You appear to
be the only one who calls them a relay.
Click to expand...
Google. Lots of examples.

But call them fluglemarts if you like.


--

John Larkin Highland Technology, Inc

jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser drivers and controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro acquisition and simulation
 
On Tue, 16 Jul 2013 17:57:50 -0700, John Larkin wrote:

Strowgers (no 'a')
Click to expand...
Named for a Kansas City undertaker.

--
"For a successful technology, reality must take precedence
over public relations, for nature cannot be fooled."
(Richard Feynman)
 
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