Using an indicator lamp with 120v

[kevreh]

I want a simple on/off indicator for a switch that's controlling an
outlet. It sounds like a neon indicator lamp is the way to go. What I'm
wondering is if the amps pulled by whatever I have plugged in could fry
the bulb. Or do they have a resistor built in to the lamps to protect
against this? If not, should I include something?

Also, should the lamp be wired in series or parallel FROM the switch?
Btw, would using an LED be more hassle (wiring)?


Thanks!
Kevin

 

[Mike]

Would an illuminated wall switch suffice? Leviton makes these...

Mike

"kevreh" <kevin2@rehbeins.com> wrote in message
news:1102970028.436157.8050@f14g2000cwb.googlegroups.com...

I want a simple on/off indicator for a switch that's controlling an
outlet. It sounds like a neon indicator lamp is the way to go. What I'm
wondering is if the amps pulled by whatever I have plugged in could fry
the bulb. Or do they have a resistor built in to the lamps to protect
against this? If not, should I include something?

Also, should the lamp be wired in series or parallel FROM the switch?
Btw, would using an LED be more hassle (wiring)?


Thanks!
Kevin

 

[Bill Bowden]

kevreh wrote:

I want a simple on/off indicator for a switch that's controlling an
outlet. It sounds like a neon indicator lamp is the way to go. What
I'm
wondering is if the amps pulled by whatever I have plugged in could
fry
the bulb. Or do they have a resistor built in to the lamps to protect
against this? If not, should I include something?

Also, should the lamp be wired in series or parallel FROM the switch?
Btw, would using an LED be more hassle (wiring)?


Thanks!
Kevin

If you use a neon indicator in parallel with the switch
(from one side to the other), it will light when the
switch is off and there is something plugged into the
outlet which is turned on. The neon indicator bulb should
have a 100K resistor in series for 120VAC operation.
Some are built in, others are not.

-Bill

 

[kevreh]

Dumb question, but would the resistor be before or after the lamp (I'm
guessing before since its their to prevent excess amperage from being
pulled).

 

[kevreh]

Are you sure? I was planning on taking the hot FROM the switch to one
lead of the lamp and a neutral lead that supplies the outlet to the
other lead of the lamp. My terminoligy isn't all that great so some of
what I'm saying may be misleading )

 

[John G]

"kevreh" <kevin2@rehbeins.com> wrote in message
news:1102975688.468001.95050@c13g2000cwb.googlegroups.com...

Are you sure? I was planning on taking the hot FROM the switch to one
lead of the lamp and a neutral lead that supplies the outlet to the
other lead of the lamp. My terminoligy isn't all that great so some of
what I'm saying may be misleading )

And if your terminology is bad your understanding of electricity is even
worse.

Much of the advice given above, though technically correct, could lead
a novice such as yourself to your DEATH.

I never cease to be worried about the technical and complicated answers
given on some of these Electrical news groups to absolute novices who
are way out of their depth in what they are attempting.
--
John G

Wot's Your Real Problem?

 

[John Fields]

On 13 Dec 2004 14:03:49 -0800, "kevreh" <kevin2@rehbeins.com> wrote:

Dumb question, but would the resistor be before or after the lamp (I'm
guessing before since its their to prevent excess amperage from being
pulled).

---
If you left a little of the previous message in your reply it would
make it much easier for whoever you're responding to to reply.

--
John Fields

 

[John Fields]

On 13 Dec 2004 14:08:08 -0800, "kevreh" <kevin2@rehbeins.com> wrote:

Are you sure? I was planning on taking the hot FROM the switch to one
lead of the lamp and a neutral lead that supplies the outlet to the
other lead of the lamp. My terminoligy isn't all that great so some of
what I'm saying may be misleading )

---
If you left a little of the previous message in your reply it would
make it much easier for whoever you're responding to to reply.

--
John Fields

 

[Roger Johansson]

Randy Day <ruthal@sasktel.nex> wrote:

Just like with BASIC physics, BASIC calculus and
BASIC carpentry, you're expected to have some
familiarity with BASIC math, BASIC equations and BASIC
power tools before you attempt any of the above.

It is also useful to know the prefixes in the number system and the most
common units. 975mhz means nothing. 975mHz means 975 milliherz, 975MHz
means 975 million Herz, 1 kHz means 1000 Herz, etc..

Learn the prefixes kilo, Mega, milli, micro, nano, deci, etc.. and how to
use them.

Learn some basics about Ohms law, series and parallell, etc..

Don't touch any voltage above 40 Volt until you know a lot more about
electronics and safety precautions.

It is all available at any public library in the world, or through
internet.


--
Roger J.

 

[kevreh]

Sorry if it sounds like I'm "copping an attitude" (I feel like I'm in
high school or something). Since this forum is titled BASIC I thought
people here would be fine answering what I thought would be basic
questions.

There's nothing wrong with taking classes or reading books as you've
mentioned. But there's also nothing wrong with reading and learning on
discussion groups like this.

 

[John Fields]

On Tue, 14 Dec 2004 13:05:02 -0500, "kevreh"
<kevin2@REMOVEMErehbeins.com> wrote:

I regret ever posting my question here. The feedback I've gotten has reduced
me to someone who doesn't know anything about electronics- which is far from
the truth.

I'll find my answers elsewhere, as there are many other forums out there
that aren't as antagonistic towards someone. Most forums run on the mantra
of "there's no dumb questions", however this one seems to thrive on telling
people how ignorant they are.

---
Geez...

Didn't my reply to your original post tell you how to do it?

--
John Fields

 

[kevreh]

Ok, this is all very good info and more than enough to accomplish what I set
out to do (a light to indicate power when a switch is on). I'm still
surprised that the amperage doesn't come into play.... Thanks everyone for
the clarification.

Kevin

 

[Dbowey]

kevreh posted:

<< Ok, this is all very good info and more than enough to accomplish what I set
out to do (a light to indicate power when a switch is on). I'm still surprised
that the amperage doesn't come into play.... Thanks everyone for the
clarification.

If you are talking about the "amperage" for the lamp, it *does* come into play.
The current through the lamp and dropping resistor should be about 1 mA
according to the data at the link I posted. That's assuming the resistor was
properly sized. Let us know what you calculate. By the way, the voltage drop
across the neon bulb will remain somewhat constant for some range of current -
it's been used as a poor-man's voltage regulator.

Don

 

[Bill Bowden]

The traditional 120V neon pilot assembly is apparently obsolete

Could be. The NE-2 is still available surplus at Jameco.com for
35 cents.

http://www.jameco.com/webapp/wcs/stores/servlet/CategoryDisplay?storeId=10001&catalogId=10001&langId=-1&categoryId=11322
-Bill

 

[Jonathan Kirwan]

On 15 Dec 2004 03:20:18 GMT, dbowey@aol.com (Dbowey) wrote:

If you are talking about the "amperage" for the lamp, it *does* come into play.

Yes.

The current through the lamp and dropping resistor should be about 1 mA
according to the data at the link I posted. That's assuming the resistor was
properly sized. Let us know what you calculate.

I usually just toss a 100k to 120k in series for 110-120V, though I've used 56k
and up. About what Bill had said earlier.

By the way, the voltage drop
across the neon bulb will remain somewhat constant for some range of current -
it's been used as a poor-man's voltage regulator.

For which I've used it, too, as part of my Geiger counter to control the voltage
to the Geiger tube. A nice string of them, easily adjusted to "close enough" by
adding or subtracting one. Affirmative indication that the voltage is adequate,
too.

Jon

 

[John Fields]

On 13 Dec 2004 12:33:48 -0800, "kevreh" <kevin2@rehbeins.com> wrote:

I want a simple on/off indicator for a switch that's controlling an
outlet. It sounds like a neon indicator lamp is the way to go. What I'm
wondering is if the amps pulled by whatever I have plugged in could fry
the bulb.

---
They can't.
---

Or do they have a resistor built in to the lamps to protect
against this?

---
on some lamps there's a resistor built into the lamp, but not to
pritect it from the amps the load is pulling, it's to keep the current
which is making the lamp light up from getting large enough to hurt
the lamp.
---

If not, should I include something?

---
Yes. about a 220k ohm 1/4 watt resistor in series with the lamp.
---

Also, should the lamp be wired in series or parallel FROM the switch?

---
I should be wired from the load side of the switch to neutral, but if
you don't know what you're doing you could kill yourself.
---

Btw, would using an LED be more hassle (wiring)?

---
_Very_ much more.


--
John Fields

 

[Robert Monsen]

kevreh wrote:

I want a simple on/off indicator for a switch that's controlling an
outlet. It sounds like a neon indicator lamp is the way to go. What I'm
wondering is if the amps pulled by whatever I have plugged in could fry
the bulb. Or do they have a resistor built in to the lamps to protect
against this? If not, should I include something?

Also, should the lamp be wired in series or parallel FROM the switch?
Btw, would using an LED be more hassle (wiring)?

The indicator needs to be parallel to the load.

You can use an LED by using a diode pointing in the other direction in
parallel with it, and a resistor to drop the current to something
managable...

A 1/2W 100k resistor will drop the current to 170/100k = 1.7mA peak. The
dissipation in the resistor will be 120^2/100k = 144mW.

You also should use a 1/8A fuse. You can get ones that look like little
resistors that will work perfectly for this.

Line --- fuse ---- resistor --- antiparallel LEDs --- Neutral

Line is the little rectangular hole, Neutral is the big rectangular hole.

Make sure Neutral is within 10VAC of the big round hole, ie, ground. If
not, don't do this, and call an electrician.

US 120VAC ONLY WITHOUT EXPLICIT INFORMATION FROM COUNTRY IN QUESTION.

.-------. 100k 1/4W
| | _ ___
-----| | | |-o \_/o--|___|----o------.
| | | | | |
| | | 1/8 A | |
| | o | V - LEDs or Diodes
| | | - ^ One Up
| '-------' | | One Down
| | | |
| | | |
|--------|----------------------o------'
| |
| _ |
| / \ |
----(_/_)---|
\_/

AC Meter Should
Read < 10VAC

Tape everything upstream of the 100k resistor
(created by AACircuit v1.28 beta 10/06/04 www.tech-chat.de)

If the LEDs aren't bright enough, you can use a lower value resistor. Be
careful, however, about dissipation. The formula for heat generated is

V^2/R

So, as R decreases, the heat increased. 1/2 R will double the heat,
meaning a bigger (1/2W maybe?) resistor.

A 47k resistor in place of the 100k resistor would dissipate about
300mW, so a 1/4W resistor wouldn't work.

--
Regards,
Robert Monsen

"Your Highness, I have no need of this hypothesis."
- Pierre Laplace (1749-1827), to Napoleon,
on why his works on celestial mechanics make no mention of God.

 

[kevreh]

"John G" <Greentest@ozemail.com.au> wrote in message
news:4zovd.4$6f4.527@nnrp1.ozemail.com.au...

"kevreh" <kevin2@rehbeins.com> wrote in message
news:1102975688.468001.95050@c13g2000cwb.googlegroups.com...
Are you sure? I was planning on taking the hot FROM the switch to one
lead of the lamp and a neutral lead that supplies the outlet to the
other lead of the lamp. My terminoligy isn't all that great so some of
what I'm saying may be misleading )


And if your terminology is bad your understanding of electricity is even
worse.

Not so sure about that. I understand and respect electricity, just a bit
fuzzy on the right words to describe the concept I'm trying to explain.

Much of the advice given above, though technically correct, could lead a
novice such as yourself to your DEATH.

This is intimidating but not helpfull, especially for a forum about basic
electronics. Am I supposed to give up on this project? Why don't you share
your insight on the SAFE way to proceed raise the bar on the quality of this
discussion.

I never cease to be worried about the technical and complicated answers
given on some of these Electrical news groups to absolute novices who are
way out of their depth in what they are attempting.

Again, the group is titled "BASIC"

John G

Wot's Your Real Problem?

 

[John G]

"kevreh" <kevin2@REMOVEMErehbeins.com> wrote in message
news:ckqvd.6636$7p.1590@lakeread02...

"John G" <Greentest@ozemail.com.au> wrote in message
news:4zovd.4$6f4.527@nnrp1.ozemail.com.au...

"kevreh" <kevin2@rehbeins.com> wrote in message
news:1102975688.468001.95050@c13g2000cwb.googlegroups.com...
Are you sure? I was planning on taking the hot FROM the switch to
one
lead of the lamp and a neutral lead that supplies the outlet to the
other lead of the lamp. My terminoligy isn't all that great so some
of
what I'm saying may be misleading )


And if your terminology is bad your understanding of electricity is
even worse.

Not so sure about that. I understand and respect electricity, just a
bit fuzzy on the right words to describe the concept I'm trying to
explain.

Much of the advice given above, though technically correct, could
lead a novice such as yourself to your DEATH.

This is intimidating but not helpfull, especially for a forum about
basic electronics. Am I supposed to give up on this project? Why don't
you share your insight on the SAFE way to proceed raise the bar on the
quality of this discussion.

I never cease to be worried about the technical and complicated
answers given on some of these Electrical news groups to absolute
novices who are way out of their depth in what they are attempting.

Again, the group is titled "BASIC"

I am sorry, I do not want to be insulting, but you do not have the
remotest understanding of even the most basic electric principles when
you ask questions, as you did above, like, Is the resistor to stop the
load drawing too much power? or Should the lamp be wired in series or
parallel? or Should the resistor be before or after the lamp?

Yes this is a Basic group but it is not possible to teach first
principles of a subject as complicated as Electricity by answering
random questions. Some understanding is first required.

And I repeat, from your very limited knowledge displayed above you hould
stay away from even 120volts, it does kill.
--
John G

Wot's Your Real Problem?

 

[Randy Day]

kevreh wrote:

[snip]

Much of the advice given above, though technically correct, could lead a
novice such as yourself to your DEATH.


This is intimidating but not helpfull, especially for a forum about basic
electronics. Am I supposed to give up on this project?

No, you're supposed to get yourself to a community college,
and take a short course in electric/electronic circuits so
you can understand what we're talking about when we use the
*basic* terminology in the subject. It doesn't get much more
basic than schematic/series/parallel/resistor/ground/hot/
electrocution.

Why don't you share
your insight on the SAFE way to proceed raise the bar on the quality of this
discussion.

I just did. Find a night course at a local high school
offering a beginner's look at electr(on)ic circuits.

Preferably with hands-on experiments, wiring practice
and reading of schematics.

I never cease to be worried about the technical and complicated answers
given on some of these Electrical news groups to absolute novices who are
way out of their depth in what they are attempting.


Again, the group is titled "BASIC"

Just like with BASIC physics, BASIC calculus and
BASIC carpentry, you're expected to have some
familiarity with BASIC math, BASIC equations and BASIC
power tools before you attempt any of the above.

Don't cop an attitude, pal. Get to a beginner's class,
and build the birdhouse before you attempt the
two-storey, split-level bungalow.

120 volts can *KILL*. 120 volts can *burn your house to
the ground.* Or both.

You've been warned.