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Using an indicator lamp with 120v

C

Clarence

Jan 1, 1970
0
kevreh said:
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.

Take care-
Kevin

You just have had some bad luck to encounter a couple of jerks who delight in
asserting them selves to make them feel like they really are somebody.

Not everyone here is like them....
 
P

petrus bitbyter

Jan 1, 1970
0
kevreh said:
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.

Take care-
Kevin

Kevin,

Your questions had hardly to do with electronics. Just some basic
electricity. The questions you posted made me deduce that you have little
knowledge or experience. Your reactions only confirm. No one blames you for
the questions and you also got answers. If you get some better answers
elsewhere, please let us know. Most of us are still willing to learn. No
reason to become angry because we urge you to be carefull.

petrus bitbyter
 
R

Rich Grise

Jan 1, 1970
0
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.

Actually, it's you who copped a 'tude. You got at least four good answers,
and immediately started questioning them, as if you either thought you
already had a better answer, or were not grasping the concepts presented.
At that point, people started suggesting background material, which seems
to have pressed your hotbutton.

If you have no interest in making any effort on your own part to figure
out how to apply the answers you get even in a basics group, then you will
probably not be missed too terribly.

Good Luck,
Rich
 
K

kevreh

Jan 1, 1970
0
I wasn't so much questioning as clarifying. Nothing wrong with that if
I wasn't grasping the concepts.

I know my questions probably weren't worded the best.... I understand
that it would be more helpful and less confusing if I spoke with the
correct terminology (I was hoping a group like this would help). Due to
my less than ideal wording I think some people have made assumptions
about my electrical know how. I have a firm grasp on the basics (ohms
law, serial vs parallel, 120 vs 240, types of switches, what
resistors/capacitors/diodes do, how to work safely around electricity,
etc...)....I'm just looking to learn more.

Its' too bad this thread had to degrade, sorry, if its' not to late to
get it back on track can someone clarify the following:

Comment: Bill said: "The neon indicator bulb should have a 100K
resistor in series for 120VAC operation. Some are built in, others are
not." John said: "it's to keep the current which is making the lamp
light up from getting large enough to hurt
the lamp."...
Question: Is the resistor to protect the bulb from voltage spikes by
the device(s) plugged into the outlet?
 
J

John G

Jan 1, 1970
0
kevreh said:
I wasn't so much questioning as clarifying. Nothing wrong with that if
I wasn't grasping the concepts.

I know my questions probably weren't worded the best.... I understand
that it would be more helpful and less confusing if I spoke with the
correct terminology (I was hoping a group like this would help). Due
to
my less than ideal wording I think some people have made assumptions
about my electrical know how. I have a firm grasp on the basics (ohms
law, serial vs parallel, 120 vs 240, types of switches, what
resistors/capacitors/diodes do, how to work safely around electricity,
etc...)....I'm just looking to learn more.

Its' too bad this thread had to degrade, sorry, if its' not to late to
get it back on track can someone clarify the following:

Comment: Bill said: "The neon indicator bulb should have a 100K
resistor in series for 120VAC operation. Some are built in, others are
not." John said: "it's to keep the current which is making the lamp
light up from getting large enough to hurt
the lamp."...
Question: Is the resistor to protect the bulb from voltage spikes by
the device(s) plugged into the outlet?

No. the resistor is to limit the normal current thru the lamp.

A NEON lamp will not conduct at all until some strike voltage is reached
and then it has a very small resistance and will destroy itself. The
resistor is to limit this current to a safe level whilst allowing
enough current to see the light.
The strike voltage is generally something above 60 volts. The running
current with 110 volts and 100k resistor is about 1mA (Yes it is
probably more complicated than just I = E/R but that is near enough for
this example.)

LEDs also need a resistor to limit the current but their voltage is much
lower and are not great for 110 volts without another diode in reverse
to drop the voltage when it reverses. NEONs conduct both directions. And
the drop in the resistor and hence the wasted power(heat) is greater.
 
D

Dbowey

Jan 1, 1970
0
kevreh posted, in part:

<< Is the resistor to protect the bulb from voltage spikes by the device(s)
plugged into the outlet?
No! It is to limit the current through the bulb. As I recall, the NE2 type
bulb fires at about 60VAC. I took a quick look via Google, for a spec sheet
and found some info here:

<A HREF="http://www.donsbulbs.com/cgi-bin/r/b.pl/ne2-usa.html">#NE2-USA - bulb
lamp - bulbs lamps</A>

The table lists the operating voltage range for both AC and DC operation.
Since you have a grasp of Ohm's Law, you can verify the suggested resistor
value.

Don
 
J

John Fields

Jan 1, 1970
0
I wasn't so much questioning as clarifying. Nothing wrong with that if
I wasn't grasping the concepts.

I know my questions probably weren't worded the best.... I understand
that it would be more helpful and less confusing if I spoke with the
correct terminology (I was hoping a group like this would help). Due to
my less than ideal wording I think some people have made assumptions
about my electrical know how. I have a firm grasp on the basics (ohms
law, serial vs parallel, 120 vs 240, types of switches, what
resistors/capacitors/diodes do, how to work safely around electricity,
etc...)....I'm just looking to learn more.

Its' too bad this thread had to degrade, sorry, if its' not to late to
get it back on track can someone clarify the following:

Comment: Bill said: "The neon indicator bulb should have a 100K
resistor in series for 120VAC operation. Some are built in, others are
not." John said: "it's to keep the current which is making the lamp
light up from getting large enough to hurt
the lamp."...
Question: Is the resistor to protect the bulb from voltage spikes by
the device(s) plugged into the outlet?

---
No, the resistor is there because when the gas in the lamp ionizes at
somewhere between about 90 to 140 volts, the resistance of the lamp
goes from essentially an open circuit to a fairly low value which,
without the series resistor will seriously shorten the lifetime of the
lamp by allowing currents large enough to flow through the lamp to
damage it.

Check:

http://www.gilway.com/pdf/appl-neonlamps.pdf


Using a fixed-pitch font like Courier to view the following, if you
have a neutral wire coming into the switchbox and you want to locate
the lamp in the same box with the switch, you'll need to hook it up
like this:


SWITCHBOX
+----------------------+
| |
ACHOT>--------------------> | |
| | |
| O |
| | |
ACNEUT>-----[LAMP]--[220K]--+ |
| | |
+-------------------|--+
|
|
ACNEUT>---------[LOAD]------+



However, if your switchbox has no neutral wire in it, then you won't
be able to put the lamp in the same switchbox with the switch and
you'll either have to put it in parallel with the load or find another
neutral wire somewhere else, like this:


SWITCHBOX
+-------+
| |
ACHOT>--------------------> | |
| | |
| O |
+----|--+
|
|
ACNEUT>---------[LOAD]------+
|
|
ACNEUT>-----[LAMP]--[220K]--+


Again, if you don't understand what you're getting into you could kill
yourself, so if you do, don't come back complaining that you weren't
warned!^)
 
R

Rich Grise

Jan 1, 1970
0
I wasn't so much questioning as clarifying. Nothing wrong with that if
I wasn't grasping the concepts.

I know my questions probably weren't worded the best.... I understand
that it would be more helpful and less confusing if I spoke with the
correct terminology (I was hoping a group like this would help). Due to
my less than ideal wording I think some people have made assumptions
about my electrical know how. I have a firm grasp on the basics (ohms
law, serial vs parallel, 120 vs 240, types of switches, what
resistors/capacitors/diodes do, how to work safely around electricity,
etc...)....I'm just looking to learn more.

Your claim that you have a "firm grasp on the basics" with your list of
buzzwords is shown to be simply not true based on your question itself.

There is no shame in not knowing. We were all there once. Admitting that
you do not know is the first stage of wisdom.

And now, John G, Dbowey, and John Fields have all given you excellent
answers. I could have done as well, but these other fellows are obviously
orders of magnitude less lazy than I am. :)

Welcome to the asylum!
Rich
 
K

kevreh

Jan 1, 1970
0
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
 
J

John G

Jan 1, 1970
0
kevreh said:
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
Again not wanting to offend you Kevin.

If I was a prosecutor I would have to say "I rest my case Your Honour."

In a parallel circuit as we have described here.
There is no relation between the current in the lamp and the current in
the load until the current in the load is so high that it starts to
affect and drag down the source, whatever it might be.
If the supply is the 120 volt network that will take a very big load or
blow the supply fuse at maybe 10 or 20 amps which should occur before
the voltage falls noticeably.

This is all simple Ohms Law stuff.
 
D

Dbowey

Jan 1, 1970
0
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
 
J

Jonathan Kirwan

Jan 1, 1970
0
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
 
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