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John Fields
electronics forum Guru
Joined: 24 Mar 2005
Posts: 3260
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 Posted: Thu Mar 24, 2005 6:01 pm Post subject:
Re: Simple Battery Monitor Circuit Required
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On Fri, 4 Feb 2005 18:51:25 -0500, "jsmith" <juddo@ix.netcom.com>
wrote:
| Quote: | Geese, what a lot of irrelevant questions!!!
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Irrelevant in what respect?
--
John Fields |
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Blackbeard
electronics forum beginner
Joined: 24 Mar 2005
Posts: 9
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| Posted: Thu Mar 24, 2005 6:01 pm Post subject:
Re: TESLA COIL
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Larry,
Thanks for your thoughts regarding safety. Once we get "first light"
we've already arranged a face-to-face meeting/demonstration with the
electronics instructor at the community college. The guy has a PhD and
lots and lots of experience. This fellow is our last stop before my
son placed his project in the science fair. The school gave us a
couple of extra days because they agree the this meeting will be
important.
In addition, the instructor at the community college has already shown
him how to read the wiring diagram. He's learned quite a bit from this
one project. We're putting on our final touches today (I hope). Our
first 1/2-dozen attempts failed to produce streamers. But I think
we're close.
We went ahead and found a plastic storage box that houses all the high
voltage stuff nicely and keep them out-of-reach from the curious. He's
pretty jived by this whole thing. He's already talking about building
his next coil and he hasn't finished his first.
The is another fellow who is an electrical engineer who has given him
some help. He's also talked to a motor shop where they re-build
electric components. So he's doing all the footwork. Can't figure out
why it hasn't worked yet. But I think it's going to be pretty great
when it does.
thanks
mike
On Fri, 4 Feb 2005 14:13:30 -0800, "Larry Brasfield"
<donotspam_larry_brasfield@hotmail.com> wrote:
| Quote: | Not much electronics in this post. You've been warned.
"Blackbeard" <Blackbeard_The_Great@Lycos.com> wrote in message
news:75mnv0t7knvc32gm7bcf5csujav2odku1s@4ax.com...
My kid is building a tesla coil for his science fair project.
From what you've written about this, I hope it does not
become a disappointment or problem. So I offer this
unsolicited advice:
Your son, or somebody on his behalf, should get this
demonstration approved before the big day. If this
has not been done, with safety procedures and signs
in place that are satisfactory to whoever is in charge
of the fair, there is a good chance that somebody in
chage will freak out when the Tesla coil is run, and
shut it down for the day. And I would not count on
such people to be technically savvy enough to know
what the real hazards are versus imagined hazards.
That is why some early discussions are in order. |
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Bill Carson
electronics forum beginner
Joined: 24 Mar 2005
Posts: 7
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Thomas A. Horsley
electronics forum beginner
Joined: 02 May 2005
Posts: 19
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| Posted: Thu Mar 24, 2005 6:01 pm Post subject:
Re: Serail port in winxp
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| Quote: | I am doing a project which requires serial port to be acessed in
winxp.Please help me
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Unlike many other devices, there are very few features of the serial port
you can't get at using the native win32 interfaces. For some examples, see
the program I wrote while trying to figure out the interface of COM2 pins on
my asus motherboard:
description: http://home.att.net/~Tom.Horsley/p4c800e.html
program: http://home.att.net/~Tom.Horsley/rs232.zip
--
<URL:http://home.att.net/~Tom.Horsley> Free Software and Politics <<==+ |
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John Fields
electronics forum Guru
Joined: 24 Mar 2005
Posts: 3260
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| Posted: Thu Mar 24, 2005 6:01 pm Post subject:
Re: Simply question
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On Wed, 09 Feb 2005 18:54:39 GMT, "Chris Lewis"
<christopher.lewis@tiscali.co.uk> wrote:
| Quote: | I want to build a simple cable that will mute the speakers on my computer
when i plug in headphones. I guess i can do it with a 3.5mm plug and a
coule of 3.5mm sockets.
I need some way of connecting them so that one output loses its connection
when the other is connected.
I tried google but didnt find anything usefull. If anyone could point me in
the direction of a circuit diagram and also somewhere good to buy the parts
in the UK it would be really appreciated.
|
---
Click on this:
8ouk01tb0gibdff7guts1nokm4hocr5che@4ax.com
--
John Fields |
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Chris Lewis
electronics forum beginner
Joined: 09 Feb 2005
Posts: 11
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| Posted: Thu Mar 24, 2005 6:01 pm Post subject:
Re: Simply question
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"John Fields" <jfields@austininstruments.com> wrote in message
news:0uuk01hbvp7n6iv7vlde0su3hum72s471h@4ax.com...
| Quote: | On Wed, 09 Feb 2005 18:54:39 GMT, "Chris Lewis"
christopher.lewis@tiscali.co.uk> wrote:
I want to build a simple cable that will mute the speakers on my computer
when i plug in headphones. I guess i can do it with a 3.5mm plug and a
coule of 3.5mm sockets.
I need some way of connecting them so that one output loses its connection
when the other is connected.
I tried google but didnt find anything usefull. If anyone could point me
in
the direction of a circuit diagram and also somewhere good to buy the
parts
in the UK it would be really appreciated.
---
Click on this:
8ouk01tb0gibdff7guts1nokm4hocr5che@4ax.com
--
John Fields
|
This just tries to send an e-mail to that address, I'm sure that was not
what you intended. was it a link to a news post? If yes can I have the
subject and date so I can try to find it on Google.
Thanks again
Chris |
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tkirk
electronics forum beginner
Joined: 24 Mar 2005
Posts: 4
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| Posted: Thu Mar 24, 2005 6:01 pm Post subject:
Re: RS-232 Question
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I know this thread is a bit old, but thought I'd reply anyway in case
anyone is doing a search on a similar problem.
At the company I work for (Rogue Engineering Inc.), we ran into a
similar problem where we were trying to set up a radio
converter/repeater station that also had a PLC attached to it.
Essentially, we needed a full 3-way communications hub for serial data
at RS-232 signal levels. To solve this problem, we designed a 3 port
half-duplex RS-232 hub. The 3 ports are identical, and any incoming
message to one of the hubs ports will be echoed out the other 2 ports.
While a message is incoming on one port, the other two ports are locked
out from incoming messages until the first port is done, and a short
time-out period (~1 ms) has expired. It works great as long as you are
using a half-duplex communication protocol, such as Modbus, and is much
better than the so-called "smart" data switches I've seen out there
that require you to modify your communications protocol to work with
them.
We also decided to go ahead and sell the device to the public. It is
available from a distributor we work with, RawIQ for approximately
$100. Their website is www.rawiq.com Both DB-9 and euroterm wiring
connectors are available for each of the 3 ports. Total current
consumption is less than 20mA typical including RS-232 drivers at a
single supply voltage of between 4 and 18V.
Tim Kirk
tkirk@rogue-engr.com
Electronics Design Engineer
www.rogue-engr.com
Steve Fisher wrote:
| Quote: | A while back I asked this question and received the following answer.
I tried to build the device in the ANSWER, but I can't get it to
work.
Any ideas as to what is wrong?
QUESTION:
I am currently working on a project that requires I connect a device
mid-stream in an RS-232 connection to send data to one end.
The system I am trying to connect to:
There are two computers (A and B) currently connected via an RS-232
cable. I want to connect a device (like a barcode scanner) to one end
and have it send data to the other but I still need the two computers
to carry on a "normal" RS-232 conversation.
Basically this is an RS-232 wedge.
ANSWER:
Based on your message, it looks like you can do it nicely
with two signal diodes, 1N4148, and two 4.7K resistors.
When the RS-232 devices are all idle, there is a negative voltage on
the signal lines. Data is transmitted by pulling the signal lines
positive in pulses. I'll attempt a drawing....
(NOTE: This "drawing" must be displayed in a fixed font such as
Courier to line up correctly)
computer 1 -------4.7Kresistor--------|
| 1N4148 | |
|------|>|---------| |
|-------- computer 2
|------|>|---------| |
| 1N4148 | |
Handheld -------4.7Kresistor--------|
The resistors and diodes "isolate" the two sending devices from
each other but still allow them to talk to computer 2.
The network only has to be put into the line for one wire, the
one connected to computer 2's input. |
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John Fields
electronics forum Guru
Joined: 24 Mar 2005
Posts: 3260
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| Posted: Thu Mar 24, 2005 6:01 pm Post subject:
Re: Simply question
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On Wed, 09 Feb 2005 22:13:15 GMT, "Chris Lewis"
<christopher.lewis@tiscali.co.uk> wrote:
| Quote: |
"John Fields" <jfields@austininstruments.com> wrote in message
news:0uuk01hbvp7n6iv7vlde0su3hum72s471h@4ax.com...
On Wed, 09 Feb 2005 18:54:39 GMT, "Chris Lewis"
christopher.lewis@tiscali.co.uk> wrote:
I want to build a simple cable that will mute the speakers on my computer
when i plug in headphones. I guess i can do it with a 3.5mm plug and a
coule of 3.5mm sockets.
I need some way of connecting them so that one output loses its connection
when the other is connected.
I tried google but didnt find anything usefull. If anyone could point me
in
the direction of a circuit diagram and also somewhere good to buy the
parts
in the UK it would be really appreciated.
---
Click on this:
8ouk01tb0gibdff7guts1nokm4hocr5che@4ax.com
--
John Fields
This just tries to send an e-mail to that address, I'm sure that was not
what you intended. was it a link to a news post? If yes can I have the
subject and date so I can try to find it on Google.
|
---
It's a link (a message ID) to a schematic I posted for you on
alt.binaries.schematics.electronic. You can find it over there under
the subject heading: "Stereo jack from SED - stereo.pdf"
--
John Fields |
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dB
electronics forum beginner
Joined: 30 Apr 2005
Posts: 22
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| Posted: Thu Mar 24, 2005 6:01 pm Post subject:
Re: Simply question
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"Chris Lewis" <christopher.lewis@tiscali.co.uk> wrote in message news:<P%sOd.217$Ha7.54@newsfe2-gui.ntli.net>...
| Quote: | I want to build a simple cable that will mute the speakers on my computer
when i plug in headphones. I guess i can do it with a 3.5mm plug and a
coule of 3.5mm sockets.
I need some way of connecting them so that one output loses its connection
when the other is connected.
I tried google but didnt find anything usefull. If anyone could point me in
the direction of a circuit diagram and also somewhere good to buy the parts
in the UK it would be really appreciated.
Thanks
Chris
|
CPC carry two 3.5mm switched jack sockets.
Order code CN00651 panel mount
Order code CN00652 p.c.b mount
Use one of those wired so that the signals a.e connected to the
'speakers when no plug is inserted.
Inserting the 'phones plug will disconnect the 'speakers. |
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Lord Garth
electronics forum Guru
Joined: 24 Mar 2005
Posts: 363
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| Posted: Thu Mar 24, 2005 6:01 pm Post subject:
Re: Good News! --
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Spammers go to hell.... |
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John G
electronics forum addict
Joined: 25 Mar 2005
Posts: 80
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| Posted: Thu Mar 24, 2005 6:01 pm Post subject:
Re: Simply question
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"John Fields" <jfields@austininstruments.com> wrote in message
news:4dcl01tp4i223ufqgfk827fd9t440fimil@4ax.com...
| Quote: | On Wed, 09 Feb 2005 22:13:15 GMT, "Chris Lewis"
christopher.lewis@tiscali.co.uk> wrote:
"John Fields" <jfields@austininstruments.com> wrote in message
news:0uuk01hbvp7n6iv7vlde0su3hum72s471h@4ax.com...
On Wed, 09 Feb 2005 18:54:39 GMT, "Chris Lewis"
christopher.lewis@tiscali.co.uk> wrote:
I want to build a simple cable that will mute the speakers on my
computer
when i plug in headphones. I guess i can do it with a 3.5mm plug
and a
coule of 3.5mm sockets.
I need some way of connecting them so that one output loses its
connection
when the other is connected.
I tried google but didnt find anything usefull. If anyone could
point me
in
the direction of a circuit diagram and also somewhere good to buy
the
parts
in the UK it would be really appreciated.
---
Click on this:
8ouk01tb0gibdff7guts1nokm4hocr5che@4ax.com
--
John Fields
This just tries to send an e-mail to that address, I'm sure that was
not
what you intended. was it a link to a news post? If yes can I have
the
subject and date so I can try to find it on Google.
---
It's a link (a message ID) to a schematic I posted for you on
alt.binaries.schematics.electronic. You can find it over there under
the subject heading: "Stereo jack from SED - stereo.pdf"
--
John Fields
|
Well like Chris said it just starts a new email to that address.
Could you please explain how it links to whatever.
--
John G
Wot's Your Real Problem? |
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Lord Garth
electronics forum Guru
Joined: 24 Mar 2005
Posts: 363
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| Posted: Thu Mar 24, 2005 6:01 pm Post subject:
Re: Simply question
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"John G" <Greentest@ozemail.com.au> wrote in message
news:fFAOd.32$R_5.2243@nnrp1.ozemail.com.au...
| Quote: |
"John Fields" <jfields@austininstruments.com> wrote in message
news:4dcl01tp4i223ufqgfk827fd9t440fimil@4ax.com...
On Wed, 09 Feb 2005 22:13:15 GMT, "Chris Lewis"
christopher.lewis@tiscali.co.uk> wrote:
"John Fields" <jfields@austininstruments.com> wrote in message
news:0uuk01hbvp7n6iv7vlde0su3hum72s471h@4ax.com...
On Wed, 09 Feb 2005 18:54:39 GMT, "Chris Lewis"
christopher.lewis@tiscali.co.uk> wrote:
|
Go to the news group alt.binaries.schematics.electronic
John has posted your schematic there... |
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John G
electronics forum addict
Joined: 25 Mar 2005
Posts: 80
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| Posted: Thu Mar 24, 2005 6:01 pm Post subject:
Re: Simply question
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"Lord Garth" <LGarth@Tantalus.net> wrote in message
news:TxBOd.28895$wi2.4973@newssvr11.news.prodigy.com...
| Quote: |
"John G" <Greentest@ozemail.com.au> wrote in message
news:fFAOd.32$R_5.2243@nnrp1.ozemail.com.au...
"John Fields" <jfields@austininstruments.com> wrote in message
news:4dcl01tp4i223ufqgfk827fd9t440fimil@4ax.com...
On Wed, 09 Feb 2005 22:13:15 GMT, "Chris Lewis"
christopher.lewis@tiscali.co.uk> wrote:
"John Fields" <jfields@austininstruments.com> wrote in message
news:0uuk01hbvp7n6iv7vlde0su3hum72s471h@4ax.com...
On Wed, 09 Feb 2005 18:54:39 GMT, "Chris Lewis"
christopher.lewis@tiscali.co.uk> wrote:
Go to the news group alt.binaries.schematics.electronic
John has posted your schematic there...
It was not really MY circuit, it was for the OP, Chris. |
Yes it is at ABSE but still I do not know what the link John posted
means and if Chris had to ask in the first place, he is likely a novice
and more confused than me.
I could draw the cct with my eyes closed so don't really need it, was
just interested where the link led or did not lead too.
--
John G
Wot's Your Real Problem? |
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Lord Garth
electronics forum Guru
Joined: 24 Mar 2005
Posts: 363
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| Posted: Thu Mar 24, 2005 6:01 pm Post subject:
Re: Simply question
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"John G" <Greentest@ozemail.com.au> wrote in message
news:1dCOd.77$R_5.2798@nnrp1.ozemail.com.au...
| Quote: |
"Lord Garth" <LGarth@Tantalus.net> wrote in message
news:TxBOd.28895$wi2.4973@newssvr11.news.prodigy.com...
"John G" <Greentest@ozemail.com.au> wrote in message
news:fFAOd.32$R_5.2243@nnrp1.ozemail.com.au...
"John Fields" <jfields@austininstruments.com> wrote in message
news:4dcl01tp4i223ufqgfk827fd9t440fimil@4ax.com...
On Wed, 09 Feb 2005 22:13:15 GMT, "Chris Lewis"
christopher.lewis@tiscali.co.uk> wrote:
"John Fields" <jfields@austininstruments.com> wrote in message
news:0uuk01hbvp7n6iv7vlde0su3hum72s471h@4ax.com...
On Wed, 09 Feb 2005 18:54:39 GMT, "Chris Lewis"
christopher.lewis@tiscali.co.uk> wrote:
Go to the news group alt.binaries.schematics.electronic
John has posted your schematic there...
It was not really MY circuit, it was for the OP, Chris.
Yes it is at ABSE but still I do not know what the link John posted
means and if Chris had to ask in the first place, he is likely a novice
and more confused than me.
I could draw the cct with my eyes closed so don't really need it, was
just interested where the link led or did not lead too.
--
John G
Wot's Your Real Problem?
|
It looks like a screw up from J.F.'s post. It should be no big deal for the
OP to go
to ABSE and find it, if it is...I'm hiding now! |
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Chris Lewis
electronics forum beginner
Joined: 09 Feb 2005
Posts: 11
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| Posted: Thu Mar 24, 2005 6:01 pm Post subject:
Re: Simply question
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| Quote: | It was not really MY circuit, it was for the OP, Chris.
Yes it is at ABSE but still I do not know what the link John posted
means and if Chris had to ask in the first place, he is likely a
novice and more confused than me.
I could draw the cct with my eyes closed so don't really need it, was
just interested where the link led or did not lead too.
--
John G
Wot's Your Real Problem?
|
I think the problem is that the link needs to have news:\\ added to the
front. If you dont then the news reader just thinks it is a mailto:\\ link.
I wouldn't say i was a novice (at usenet, i think my question prooves i am
at electronics!!) it just had me a bit confused. Anyway off to check google
archives as our news server here at work doesnt carry binary groups and we
cant access anythin else!
Thanks every one for your help.
--
Chris Lewis |
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