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Sci.Electronics.Basics -> Light on a string?
There are 8 messages in this thread.
You are currently looking at messages 1 to 8.
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My sister would like to use a light on the end of a string, and I was
wondering how that could be made. I was thinking of putting a bright
LED, and resistor, and some hook-up wire in a clear, plastic ball or
even in some Saran Wrap with a battery to power the circuit. This may
be completely implausible, I don't know.
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Author: Bob MonsenDate: 22:00 16-04-08
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<chesemonkyloma@gmail.com> wrote in message
news:786a05af-57b3-44b8-80f8-e408f04cdeb7@m44g2000hsc.googlegroups.com...
> My sister would like to use a light on the end of a string, and I was
> wondering how that could be made. I was thinking of putting a bright
> LED, and resistor, and some hook-up wire in a clear, plastic ball or
> even in some Saran Wrap with a battery to power the circuit. This may
> be completely implausible, I don't know.
9V battery + ------- 1k ohm RESISTOR ---- LED ---- 9V battery -
Wrap it in saran wrap, and you have a light on a string... ;)
The long lead coming out of the LED should connect to the resistor, not
the - side of the battery. The resistor doesn't care.
You can get LEDs and resistors at radio shack, frys, or online at
www.goldmine-elec.com, www.digikey.com, www.mouser.com, www.futurlec.com,
www.arrow.com, etc.
Regards,
Bob Monsen
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Author: SkrapasorDate: 22:12 16-04-08
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On Apr 16, 10:00 pm, "Bob Monsen" <rcmon...@gmail.com> wrote:
> <chesemonkyl...@gmail.com> wrote in message
>
> news:786a05af-57b3-44b8-80f8-e408f04cdeb7@m44g2000hsc.googlegroups.com...
>
> > My sister would like to use a light on the end of a string, and I was
> > wondering how that could be made. I was thinking of putting a bright
> > LED, and resistor, and some hook-up wire in a clear, plastic ball or
> > even in some Saran Wrap with a battery to power the circuit. This may
> > be completely implausible, I don't know.
>
> 9V battery + ------- 1k ohm RESISTOR ---- LED ---- 9V battery -
>
> Wrap it in saran wrap, and you have a light on a string... ;)
>
> The long lead coming out of the LED should connect to the resistor, not
> the - side of the battery. The resistor doesn't care.
>
> You can get LEDs and resistors at radio shack, frys, or online
atwww.goldmine-elec.com,www.digikey.com,www.mouser.com,www.futurlec.com,www.arrow.com,
etc.
>
> Regards,
> Bob Monsen
Wait, how do you connect the battery then? Negative terminal-wire-
resistor-LED-wire-positive?
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Author: SkrapasorDate: 22:13 16-04-08
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Or would one lead of the LED go to the resistor and the other lead to
the battery? Also, how do you hook-up a lead or wire to a battery? I
am really new at this.
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Author: Allen BongDate: 22:48 16-04-08
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On Apr 17, 10:13=A0am, Skrapasor <chesemonkyl...@gmail.com> wrote:
> Or would one lead of the LED go to the resistor and the other lead to
> the battery? Also, how do you hook-up a lead or wire to a battery? I
> am really new at this.
Hook it up like this. I hope this is clear enough.
1K resistor
.-----------. ___ long lead of LED
| | +-|___|----------------------+
| +||-+ | __
|9V battery | +--------| \ LED
| -||------+ | )
'-----------' | +-----|__/
+--------------------------+
shorter lead of LED
(view in fixed text or courier)
(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)
Allen
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Author: Bob EldDate: 00:52 17-04-08
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<chesemonkyloma@gmail.com> wrote in message
news:786a05af-57b3-44b8-80f8-e408f04cdeb7@m44g2000hsc.googlegroups.com...
> My sister would like to use a light on the end of a string, and I was
> wondering how that could be made. I was thinking of putting a bright
> LED, and resistor, and some hook-up wire in a clear, plastic ball or
> even in some Saran Wrap with a battery to power the circuit. This may
> be completely implausible, I don't know.
When I was in College one of the guys in the dorm hung a bare 60 watt
incandescent light bulb, 120Volts, from the concrete ceiling of his room on
a piece of string. The bulb would just hang there lit, fully bright, but
looking at it you couldn't figure out how it was powered. It was a great
conversation piece and kept a lot of people guessing. A bare bulb just
hanging there on a sting without a socket or apparent wires burning away, it
was great.
What he had done is twisted some very thin magnet wire, like 36 Ga. into the
string and soldered the ends to the bulb base where the string was tied. The
wires went up the string then across the concrete ceiling hidden in the
natural cracks and roughness of the painted concrete. The string was taped
to the ceiling. You could not see the wires without climbing up and very
closely inspecting the situation. The wires came down one wall to a wall
plug where other stuff was plugged in concealing the termination.
I wouldn't recommend this as it could be a fire hazard but it sure would be
a hell of a lot more impressive than an LED. It takes a clever artistic
person to weave and conceal the thin wires. If not carefully done it would
be a dead giveaway if wires can be seen. If you try it be sure to never
leave this kind of thing plugged in unattended.
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Author: Bob MonsenDate: 18:31 17-04-08
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"Bob Eld" <nsmontassoc@yahoo.com> wrote in message
news:dIANj.5301$GO4.2306@newssvr19.news.prodigy.net...
>
> <chesemonkyloma@gmail.com> wrote in message
> news:786a05af-57b3-44b8-80f8-e408f04cdeb7@m44g2000hsc.googlegroups.com...
>> My sister would like to use a light on the end of a string, and I was
>> wondering how that could be made. I was thinking of putting a bright
>> LED, and resistor, and some hook-up wire in a clear, plastic ball or
>> even in some Saran Wrap with a battery to power the circuit. This may
>> be completely implausible, I don't know.
>
> When I was in College one of the guys in the dorm hung a bare 60 watt
> incandescent light bulb, 120Volts, from the concrete ceiling of his room
> on
> a piece of string. The bulb would just hang there lit, fully bright, but
> looking at it you couldn't figure out how it was powered. It was a great
> conversation piece and kept a lot of people guessing. A bare bulb just
> hanging there on a sting without a socket or apparent wires burning away,
> it
> was great.
>
> What he had done is twisted some very thin magnet wire, like 36 Ga. into
> the
> string and soldered the ends to the bulb base where the string was tied.
> The
> wires went up the string then across the concrete ceiling hidden in the
> natural cracks and roughness of the painted concrete. The string was taped
> to the ceiling. You could not see the wires without climbing up and very
> closely inspecting the situation. The wires came down one wall to a wall
> plug where other stuff was plugged in concealing the termination.
>
> I wouldn't recommend this as it could be a fire hazard but it sure would
> be
> a hell of a lot more impressive than an LED. It takes a clever artistic
> person to weave and conceal the thin wires. If not carefully done it would
> be a dead giveaway if wires can be seen. If you try it be sure to never
> leave this kind of thing plugged in unattended.
>
>
Is it safe?
36 ga wire has 418 ohms/1000 ft. Your friend's display probably used 6 feet
of wire. That is about 2.5 ohms. A 60W bulb uses 500mA at 120VAC, so your
friend was dissipating about 5/8 of a watt in the wire. Enough to get it
toasty, but probably not enough to start a fire. However, it exceeds the
maximum current allowed by the American wire gauge guys by 1400%...!
http://www.powerstream.com/Wire_Size.htm
When the bulb first turns on, it'll be alot more power, but only for a
second or so. Just don't hold the wire when you turn it on or you'll get
burned.
Regards,
Bob Monsen
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Author: Bob EldDate: 22:18 17-04-08
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"Bob Monsen" <rcmonsen@gmail.com> wrote in message
news:gcQNj.8663$V14.5876@nlpi070.nbdc.sbc.com...
> "Bob Eld" <nsmontassoc@yahoo.com> wrote in message
> news:dIANj.5301$GO4.2306@newssvr19.news.prodigy.net...
> >
> > <chesemonkyloma@gmail.com> wrote in message
> >
news:786a05af-57b3-44b8-80f8-e408f04cdeb7@m44g2000hsc.googlegroups.com...
> >> My sister would like to use a light on the end of a string, and I was
> >> wondering how that could be made. I was thinking of putting a bright
> >> LED, and resistor, and some hook-up wire in a clear, plastic ball or
> >> even in some Saran Wrap with a battery to power the circuit. This may
> >> be completely implausible, I don't know.
> >
> > When I was in College one of the guys in the dorm hung a bare 60 watt
> > incandescent light bulb, 120Volts, from the concrete ceiling of his room
> > on
> > a piece of string. The bulb would just hang there lit, fully bright, but
> > looking at it you couldn't figure out how it was powered. It was a great
> > conversation piece and kept a lot of people guessing. A bare bulb just
> > hanging there on a sting without a socket or apparent wires burning
away,
> > it
> > was great.
> >
> > What he had done is twisted some very thin magnet wire, like 36 Ga. into
> > the
> > string and soldered the ends to the bulb base where the string was tied.
> > The
> > wires went up the string then across the concrete ceiling hidden in the
> > natural cracks and roughness of the painted concrete. The string was
taped
> > to the ceiling. You could not see the wires without climbing up and
very
> > closely inspecting the situation. The wires came down one wall to a wall
> > plug where other stuff was plugged in concealing the termination.
> >
> > I wouldn't recommend this as it could be a fire hazard but it sure would
> > be
> > a hell of a lot more impressive than an LED. It takes a clever artistic
> > person to weave and conceal the thin wires. If not carefully done it
would
> > be a dead giveaway if wires can be seen. If you try it be sure to never
> > leave this kind of thing plugged in unattended.
> >
> >
>
>
> Is it safe?
>
> 36 ga wire has 418 ohms/1000 ft. Your friend's display probably used 6
feet
> of wire. That is about 2.5 ohms. A 60W bulb uses 500mA at 120VAC, so your
> friend was dissipating about 5/8 of a watt in the wire. Enough to get it
> toasty, but probably not enough to start a fire. However, it exceeds the
> maximum current allowed by the American wire gauge guys by 1400%...!
>
> http://www.powerstream.com/Wire_Size.htm
>
> When the bulb first turns on, it'll be alot more power, but only for a
> second or so. Just don't hold the wire when you turn it on or you'll get
> burned.
>
> Regards,
> Bob Monsen
I don't know if it was 36 Ga. or not, it might have been 34. In any case, a
watt or two, even 5 watts dissipated in a few feet of wire won't get the
wire hot. There is too much air all around that length wire for any
appreciable temperature rise. Is it safe? Hell no! I don't think I'd be
showing it to any electrical code inspectors or UL types. It's a dorm room
or party trick, not to be left unattended. It is probably no more dangerous
than a candle, however.
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