UPS for 12V DC ?

[Jasen Betts]

On 2008-08-15, Charlie Siegrist <none.active@this.time.check.back.later> wrote:

On Fri, 15 Aug 2008 11:29:15 +0000, Jasen Betts wrote:

On 2008-08-15, Charlie Siegrist <none.active@this.time.check.back.later
wrote:
On Thu, 14 Aug 2008 10:13:41 +0000, Jasen Betts wrote:

I'm not sure I understand your response. The original poster is
discussing a 12VDC supply to an answering machine via a plug-in
rectifying transformer. Please explain the danger of ring voltage
somehow appearing via the recitified AC voltage from a wall outlet?

Possibly the 0V DC input terminal of the device is connected directly
to one of the phone line wires.

Can you explain how such a design would function? I'm eager to hear.

I envisage a setup something like this:

+12V
___|____
input| | output
-----------| circuit|----------._/|
|________| |_ |
phone line | | \|
---------------+---------------'
|
0V (not grounded)

You seem to be of the opinion that such a thing is unworkable. why is
that?

You are correct in that assessment. I think it would be more to the
point that you showed me that it could work. Let's start out with a
simple question. In your drawing, which is tip and which is ring?

I intended 0V as ring but that really depends on who wired the socket.
and the device would probably have a diode bridge between the input and
the phone line to sort out that ambiguity, which would put the 0V at
nearly 48V below ground before the phone line starts to ring.

Bye.
Jasen

 

[Charlie Siegrist]

On Sun, 17 Aug 2008 13:12:21 +0000, Jasen Betts wrote:

You are correct in that assessment. I think it would be more to the
point that you showed me that it could work. Let's start out with a
simple question. In your drawing, which is tip and which is ring?

I intended 0V as ring but that really depends on who wired the socket.
and the device would probably have a diode bridge between the input and
the phone line to sort out that ambiguity, which would put the 0V at
nearly 48V below ground before the phone line starts to ring.

Ah, according to your diagram, the input *is* the phone line. I find it
odd that, given your previous cautions against monkeying with a telephone
line, you've done exactly that with your completely ambiguous "circuit."
At any rate, you've shown me that you have no clue about telephony, and
have some strange and unworkable ideas about electronic design, so I see
no reason to continue.

 

[Dave]

Hi John,

Very cool solution but why do you say, "Assuming your answering machine
doesn't draw 200 mA?"

Is that the max those diodes can use?

Dave
Google Groups: I do not see postings from GG.
I am using an account with http://www.usenet4all.se/ to weed out the
bullshit and spam. If you are responding from within Google Groups I
will not see your reply. Try usenet4all I think you will like it. It is
Usenet the way it used to be. Yes, I am THAT old! <grin>


John Fields wrote:

WALL ANS.
WART MACH
+----+ +----+
MAINS>--|~ +|--[1N5817>]-+-[1N5817>]--|+ |
| | |+ | |
| } [BAT] | |
| | | | |
MAINS>--|~ -|------------+------------|- |
+----+ +----+

JF