Searching \ for '[EE] Electric Fence indicator light - How to?' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/index.htm?key=electric+fence+indicator
Search entire site for: 'Electric Fence indicator light - How to?'.

Exact match. Not showing close matches.
PICList Thread
'[EE] Electric Fence indicator light - How to?'
2007\05\29@173155 by Carl Denk

flavicon
face
I have a farm type electric fence power supply that we use to keep
critters (deer, raccoons, etc.) out of our vegetable garden. It is 120
VAC 10 watt max input, and output is 440 - 660 VAC measured with a DMM.  
The power supply is only a transformer, with no other components. The
external circuit is a ground rod, and the hot terminal connected to
aluminum or steel wire that is insulated from earth and can go distances
measured in miles, though I only need less than 400 feet. I have had a
120 volt neon lamp indicator on the output side that lasted a season,
and recently burned out. Thinking that some resistance would help, a 10K
1/4 watt resistor was added in series with a new neon, it lasted one
day, the resistor is still OK, lamp is out. How do I make a lamp last??

2007\05\29@180208 by William Jacobs

flavicon
face
You will need to use a larger resistor if you are using a NE-2 type
lamp.  Keep current well below 1 mA.  You maybe even want to try 1/2 mA.
bill


Carl Denk wrote:

{Quote hidden}

2007\05\29@180525 by Matthew Miller

flavicon
face
Hi,

On Tue, May 29, 2007 at 05:33:30PM -0400, Carl Denk wrote:
> I have a farm type electric fence power supply that we use to keep
> critters (deer, raccoons, etc.) out of our vegetable garden. It is 120
> VAC 10 watt max input, and output is 440 - 660 VAC measured with a DMM.  
> The power supply is only a transformer, with no other components. The
> external circuit is a ground rod, and the hot terminal connected to
> aluminum or steel wire that is insulated from earth and can go distances
> measured in miles, though I only need less than 400 feet. I have had a
> 120 volt neon lamp indicator on the output side that lasted a season,
> and recently burned out. Thinking that some resistance would help, a 10K
> 1/4 watt resistor was added in series with a new neon, it lasted one
> day, the resistor is still OK, lamp is out. How do I make a lamp last??

I made one for a friend using a compact florescent bulb (I disassembled the
lamp) and a high voltage capacitor. I don't know about the lifetime of the
thing, I guess he still has it. Here is a crude ascii diagram:

High voltage <------Cap------CF Bulb------> earth ground

I didn't use a resistor since he wanted to be able to see the flash from a
distance. I think the value of the cap was 0.001 uF and 1kV. All of this was
sealed in a 1-pint canning jar.

Experiment with using a cap instead of a resistor. Good luck.

Matthew

--
"Skepticism is the highest duty and blind faith the one unpardonable sin."
   -- Thomas Henry Huxley, M.D., Essays on Controversial Questions (1889)

2007\05\29@183509 by Alan B. Pearce

face picon face
>Thinking that some resistance would help, a 10K
>1/4 watt resistor was added in series with a new neon, it lasted one
>day, the resistor is still OK, lamp is out. How do I make a lamp last??
>

Normally use about 100k with 230V, so you probably want to use about 3 100k
resistors in series - you will probably need more than one resistor to be
within the voltage rating of the resistors.

2007\05\29@183800 by Jinx

face picon face

> I have a farm type electric fence power supply that we use to keep
> critters (deer, raccoons, etc.) out of our vegetable garden. It is 120
> VAC 10 watt max input, and output is 440 - 660 VAC measured
> with a DMM

Isn't that really dangerous ? An electric fence is normally, IME, a
pulsed affair, not constant high voltage. Do you hear any interference,
like clicking, on an AM radio for example ?

If it interests you, I have a commercial "hot fence" indicator. It's based
on a 74HC04, powered by a coin cell. You hang it on the fence. There
is no electrical contact. The HV pulse triggers the 74HC04 to blink a
LED

2007\05\29@205711 by Carl Denk

flavicon
face
The unit is marketed more for your own pets like dogs and cats. They are
widely used both for livestock and small animals. Here's a link to the
manufacturer. http://www.fishock.com/  I don't think the are harmful to
normal humans and most other critters. Both the wife and I have been
zapped by it when forgetting it's on, and we are still living. I think
the battery powered units  pulse for power savings, but this is AC
powered and I don't care about the current costs. We have not noticed
any interference.

Are you saying your schematic is available, if so I would be interested,
the case is big enough to house a small circuit board and powered off
the 120 VAC.

Since the last neon lamb I had burned out, I'm going to have to order
something, so any illuminating device would be OK and could order any
other components at the same time.

Thank's so far for the comments, keep them coming.


Jinx wrote:
{Quote hidden}

2007\05\29@211658 by Jinx

face picon face
> Are you saying your schematic is available

Can probably arrange that. I did now notice that there is an
electrical connection. The pulse is moderated by a series 100k
and cap

2007\05\29@213453 by Carl Denk

flavicon
face
my E-mail: spam_OUTcdenkTakeThisOuTspamalltel.net if you would like to attach it. The 100k
plus cap is that referring to your circuit, or away to make the neon
work? The cap, rough value? I have a bunch of high voltage caps left
from a Heathkit color TV days that might work.

Reason for the light, there is a GFCI on that circuit, sometimes if
there is lightening nearby, the breaker opens. There is also on the same
breaker, 200 feet of underground plastic conduit with 120 VAC going to a
natural gas well. The fence power is just an old 2 conductor 100 foot
extension cord laying on the grass.

Jinx wrote:
>> Are you saying your schematic is available
>>    
>
> Can probably arrange that. I did now notice that there is an
> electrical connection. The pulse is moderated by a series 100k
> and cap
>
>  

2007\05\30@085341 by Timothy J. Weber

face picon face
Carl Denk wrote:
> Reason for the light, there is a GFCI on that circuit, sometimes if
> there is lightening nearby, the breaker opens. There is also on the same
> breaker, 200 feet of underground plastic conduit with 120 VAC going to a
> natural gas well. The fence power is just an old 2 conductor 100 foot
> extension cord laying on the grass.

A different solution that might be interesting - I use a buzzer wired to
a NC relay for notification when a GFCI opens on my sump pump.

Circuit and images: <6sys.no-ip.info/~tjweber/gallery/sump>
Far too many details: <timothyweber.org/taxonomy_menu/1/2/10>
--
Timothy J. Weber
http://timothyweber.org

2007\05\30@162904 by Carl Denk

flavicon
face
Thanks, like that, it's simple, and does the job. :) I use a similar on
the UPS for my standby generator, 120 VAC holds power to the power, the
NC contact goes to battery backup.

Timothy J. Weber wrote:
{Quote hidden}

2007\05\30@185158 by Sean Breheny

face picon face
The site mentions "pulses" so perhaps they are doing something more
than just sinusoidal AC. Just because your DMM reads 440-660 on the
normal VAC scale doesn't tell you what the waveform is like.

Sean

On 5/29/07, Jinx <.....joecolquittKILLspamspam@spam@clear.net.nz> wrote:
{Quote hidden}

> -

2007\05\30@193120 by Carl Denk

flavicon
face
For my unit, the whole circuit consists of one component, a transformer
with just 2 windings, each with 2 wires. connect 120 VAC to one winding
pair of wires, the other winding gets connected one wire to a ground rod
(I use a 2 foot long 1/2" EMT thinwall electrical conduit), and the
other to the fence wire. The fence wire has only that one connection.
The circuit is completed when the animal touches both the ground (earth)
and fence wire at the same time.

Some other fence controllers (power supplies) have electronics and DO
pulse, but not my cheap model.

Sean Breheny wrote:
{Quote hidden}

>> --

2007\05\30@201248 by Jinx

face picon face

> Some other fence controllers (power supplies) have electronics and
> DO pulse, but not my cheap model.

In that case then you really are measuring plain AC. If you assume it's
660VAC, you could use a standard red LED, Vf = 1.7, I = 5mA

R = (E - Vf) * 1000/ImA

R = (660 - 1.7) * 1000/5

R = 658.3 * 200

R = 131.660k

Put a reverse parallel diode (1N914) across the LED. Resistor will need
to withstand 660VAC (don't know whether you're measuring pk-pk or
RMS) and would be better made of several smaller R in series. General
purpose Rs are usually 200V rated, but err on the cautious side. If the
LED is dim you could reduce R in increments to get the brightness you
want. Rather depends on the specs of the LED

Alternatively a dropping capacitor to limit current (with suitable voltage
rating, eg 1kV). 1uF will pass approx 70mA, so 68nF will allow about
5mA through. Some examples and principles of AC-powered LEDs here

http://ourworld.compuserve.com/homepages/Bill_Bowden/page10.htm

http://www.discovercircuits.com/H-Corner/AC-Powered.htm

Google about for others


'[EE] Electric Fence indicator light - How to?'
2007\06\01@084444 by Carl Denk
flavicon
face
Thanks much!. :)   I'll try the suggestion in the next day or 2. Outdoor
work has me busy at the moment, but rain should drive me in over the
weekend. Those links look very good also.

Jinx wrote:
{Quote hidden}

2007\06\01@110141 by Bill Clawson

picon face
I haven't followed much of this string, but I would
think you could do something with a neon light bulb
and a bit of wire as an antenna, if needed.  Electric
fences don't pack a lot of current, but I would think
you could get a neon light bulb or even a small
flourescent tube to light up next to the electric
fence without physically contacting it.

--- Carl Denk <.....cdenkKILLspamspam.....alltel.net> wrote:

{Quote hidden}

ourworld.compuserve.com/homepages/Bill_Bowden/page10.htm
> >
> >
>
www.discovercircuits.com/H-Corner/AC-Powered.htm
> >
> > Google about for others
> >
> >  
> --

2007\06\01@155807 by Dwayne Reid

flavicon
face
At the risk of being obvious, why the diode across the LED?  I'd
rather see a diode in SERIES with the LED.

This would have the effect of reducing the power dissipated in the
resistor by half.  Diode has to be rated to handle the peak voltage -
1N914 doesn't cut it in this application.

dwayne

PS - diode in series works well so long as you aren't doing the
capacitor reactance trick.  IOW: series resistors only.

dwayne

At 06:11 PM 5/30/2007, Jinx wrote:

>In that case then you really are measuring plain AC. If you assume it's
>660VAC, you could use a standard red LED, Vf = 1.7, I = 5mA
>
>Put a reverse parallel diode (1N914) across the LED.


--
Dwayne Reid   <EraseMEdwaynerspam_OUTspamTakeThisOuTplanet.eon.net>
Trinity Electronics Systems Ltd    Edmonton, AB, CANADA
(780) 489-3199 voice          (780) 487-6397 fax
http://www.trinity-electronics.com
Custom Electronics Design and Manufacturing

2007\06\01@163733 by Peiserma

flavicon
face
piclist-bounces@mit.edu wrote:
> At the risk of being obvious, why the diode across the LED?

probably because the LED cannot handle 660Vac reverse voltage by itself?


2007\06\01@180012 by Jinx

face picon face

> I haven't followed much of this string, but I would
> think you could do something with a neon light bulb
> and a bit of wire as an antenna, if needed

That works as a tester for negative ion generators. The one I've
seen had two big pads, with a neon and a small cap across them.
One pad for your thumb and one pad to pick up ions. The neon
blinks when the cap has charged up to the striking voltage

2007\06\01@190715 by Jinx

face picon face
> Diode has to be rated to handle the peak voltage - 1N914
> doesn't cut it in this application

A 1N914 is tougher than an LED. The LED works fine in
one phase, the 1N914 works fine in the other

2007\06\01@213806 by Dwayne Reid

flavicon
face
I think you missed the point I was trying to make: put the diode IN
SERIES with the LED, not across it.

The resistor now has to dissipate power only half the time now, with
no effect on the LED.

Because the diode is now in series with the LED, the diode has to be
rated for the peak line voltage (plus safety margin).  The 75V PRV
rating of a 1N914 is no longer sufficient in this configuration.

dwayne

At 05:05 PM 6/1/2007, Jinx wrote:
> > Diode has to be rated to handle the peak voltage - 1N914
> > doesn't cut it in this application
>
>A 1N914 is tougher than an LED. The LED works fine in
>one phase, the 1N914 works fine in the other


--
Dwayne Reid   <dwaynerspamspam_OUTplanet.eon.net>
Trinity Electronics Systems Ltd    Edmonton, AB, CANADA
(780) 489-3199 voice          (780) 487-6397 fax
http://www.trinity-electronics.com
Custom Electronics Design and Manufacturing

2007\06\01@215413 by Dwayne Reid

flavicon
face
At 02:37 PM 6/1/2007, @spam@peisermaKILLspamspamridgid.com wrote:
>KILLspampiclist-bouncesKILLspamspammit.edu wrote:
> > At the risk of being obvious, why the diode across the LED?
>
>probably because the LED cannot handle 660Vac reverse voltage by itself?

Maybe its the summer sun getting to me.  What I said was:

"At the risk of being obvious, why the diode across the LED?  I'd
rather see a diode in SERIES with the LED.

This would have the effect of reducing the power dissipated in the
resistor by half.  Diode has to be rated to handle the peak voltage -
1N914 doesn't cut it in this application."


I understand the need for the diode in the circuit proposed by Jinx.

However . . .

The point I was trying to make was that power was being wasted
needlessly.  A simple change (diode in series with LED rather than
across) means that power is being consumed on alternate
half-cycles.  This reduces the power dissipated in the resistor by half.

Lets put some numbers on it.

660Vac average.  5 mA current.  660 * (0.005) = 3.3 Watts.  Best to
use a 5W resistor.

Change the circuit so that the diode is now in series with the
LED.  Power dissipated within the resistor magically drops by
half.  Now you can use a 2W or 3W resistor.

THAT is the point I was trying to get across.

dwayne

PS - memories of retrofitting LED indicators in industrial control
panels come rushing back (from many, many years ago).  Keeping
resistor dissipation to a minimum was important, given that the LED
clusters we built way back then ran at 20 mA or so.   Much better
LEDs available now.

dwayne

--
Dwayne Reid   <RemoveMEdwaynerTakeThisOuTspamplanet.eon.net>
Trinity Electronics Systems Ltd    Edmonton, AB, CANADA
(780) 489-3199 voice          (780) 487-6397 fax
http://www.trinity-electronics.com
Custom Electronics Design and Manufacturing

2007\06\01@232128 by Jinx

face picon face
> The resistor now has to dissipate power only half the time now,
> with no effect on the LED

Ah, I'm with you now. If Carl's 660 is pk-pk then the resistor makes
2.33W for both 1/2 cycles. Diode (1N4007 ?) in series would drop
that to 1.17W. You'd save $ with lower wattage resistors at least

(can't blame the summer sun for my dopiness - cabin fever ?)

2007\06\02@000536 by Marcel Duchamp

picon face
Jinx wrote:
>
> (can't blame the summer sun for my dopiness - cabin fever ?)
>

It's summer here... isn't it summer there too?

Don't give us any B.S. about this hemisphere, that hemisphere;  the
world's flat, don't ya know?

2007\06\02@003726 by Jinx

face picon face
> It's summer here... isn't it summer there too ?

Well, it's *not" summer. That's a kind of summer

> the world's flat, don't ya know ?

As I have cabin fever I see no reason not to go along with that but

Just so this doesn't become an aren't-we-funny tennis match

In the excellent series by Terry "I used to dress up as middle-aged
frumps, you know" Jones, Medieval Lives, I learned that Flat Earth
was the doing of......a fairly-recent American

http://observer.guardian.co.uk/comment/story/0,6903,1143405,00.html

"The idea that they thought it was flat was invented by an American
journalist by the name of Washington Irving. In 1828, he wrote a
biography of Columbus in which he described the great man confronting
the Church leaders who accused him of heresy for claiming the earth
was round when the Church taught that it was flat. The meeting never
happened and the Church never taught that the earth was flat. Irving
simply made it all up. And yet it's stuck. It's just one of the many,
many misconceptions about the medieval world that we don't seem
able to shake off"

And who says TV doesn't educate ? See the series if you get the
chance. Any of his documentaries actually, they're all good stuff.
"The Story Of One", "Barbarians", etc. Ditto Tony Robinson's
"Worst Jobs In History", "Time Team" etc

2007\06\02@021536 by Peter P.

picon face
Jinx <joecolquitt <at> clear.net.nz> writes:

> Ah, I'm with you now. If Carl's 660 is pk-pk then the resistor makes
> 2.33W for both 1/2 cycles. Diode (1N4007 ?) in series would drop
> that to 1.17W. You'd save $ with lower wattage resistors at least

If you use a series diode with a LED for higher voltage you need to put a
capacitor in parallel with the LED or it will blow on the reverse half cycle.
Try 10 nF, low voltage. The scheme that uses a cap to reduce the voltage is
better.

Peter P.





2007\06\02@080240 by Gerhard Fiedler

picon face
Dwayne Reid wrote:

> Because the diode is now in series with the LED, the diode has to be
> rated for the peak line voltage (plus safety margin).  The 75V PRV
> rating of a 1N914 is no longer sufficient in this configuration.

What guarantees here that the reverse voltage is only (mainly) at the diode
and not at the LED? They are both in reverse during the reverse cycle.

The purpose of the anti-parallel diode is to guarantee that the reverse
voltage at the LED remains low. You can use both diodes (series and
anti-parallel)...

Gerhard

More... (looser matching)
- Last day of these posts
- In 2007 , 2008 only
- Today
- New search...