Date: Fri Mar 26 13:50:22 2010

Author: William Maddox

Subject: Re: cheap spectrum lamp

Post:

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From: WC Maddox

Using a Variac I was able to get LEDs to glow at low voltage without a
current limiting resistor. To get the LED and pickle to glow at the same
time took some experimenting to select current limiting resistor and
spacing between leads stuck into pickle. If voltage across LED was too
low, it would stop glowing when pickle started glowing. If too much
voltage the LED may get fried before the pickle.

Thanks for the idea. All the hot dog did was swell up and produce steam
followed by smoke.

End Message

>
> *You can also just stick an LED into the pickle with its legs split
> along the long axis of the pickle. *The LED will glow because the
> pickle is a long resistor keeping the current through the LED down to
> reasonable levels.
>
> *When you cook hot dogs using this technique you can also stick LEDs
> into the hot dog.
> *
> Paul D
>
> Exploratorium
>
>
>
>
>
> On Mar 24, 2010, at 1:51 PM, Anthony Lapinski wrote:
>
>> Very cool! I've been doing this demo for years. Nice optics application!
>>
>> Does anyone know why only one side (usually) of the pickle glows (by the
>> nail)? Is it always near the "hot" lead/terminal. I have seen sides
>> alternate glowing, and sometimes both sides glowing simultaneously.
>>
>> Also, the pickle is a good conductor, so it should not be touched during
>> this demonstration. Right?
>>
>>
>> tap-l@lists.ncsu.edu writes:
>>> A faculty member sent this link to me today. This is a really
>>> cheap
>>> way to see the sodium doublet...
>>>
>>>>
>>>
>>>
>>>
>>> Jerry
>>
>>
>
>
>


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From: WC Maddox



Using a Variac I was able to get LEDs to glow at low voltage without a
current limiting resistor. To get the LED and pickle to glow at the
same time took some experimenting to select current limiting resistor
and spacing between leads stuck into pickle. If voltage across LED was
too low, it would stop glowing when pickle started glowing. If too much
voltage the LED may get fried before the pickle.



Thanks for the idea. All the hot dog did was swell up and produce steam
followed by smoke.



End Message



**
> **
> *You can also just stick an LED into the pickle with its legs
> split along the long axis of the pickle. *The LED will glow
> because the pickle is a long resistor keeping the current
> through the LED down to reasonable levels.
>
> *When you cook hot dogs using this technique you can also
> stick LEDs into the hot dog.
> *
> Paul D
>
> Exploratorium
>
>
>
>
>
> On Mar 24, 2010, at 1:51 PM, Anthony Lapinski wrote:
>
> **
>> **Very cool! I've been doing this demo for years. Nice optics
>> application!
>>
>> Does anyone know why only one side (usually) of the pickle
>> glows (by the
>> nail)? Is it always near the "hot" lead/terminal. I have seen
>> sides
>> alternate glowing, and sometimes both sides glowing
>> simultaneously.
>>
>> Also, the pickle is a good conductor, so it should not be
>> touched during
>> this demonstration. Right?
>>
>>
>> tap-l@lists.ncsu.edu writes:
>> **
>>> ** A faculty member sent this link to me today. This is
>>> a really
>>> cheap
>>> way to see the sodium doublet...
>>>
>>> **
>>>> **
>>>>
>>>> **
>>> **
>>>
>>>
>>> Jerry
>>> **
>> **
>>
>> **
> **
>
>
> **

**

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**

**

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