[Shop-talk] looking for small light bulbs

[Pat Horne]

Agreed.  If dimming isn't necessary I'd try a white LED and add a series 
resistor to get the desired brightness.

Peace,
Pat

Thusly spake Steven Trovato:
> Yes, yes.  I was really thinking you would just compare the resistance 
> of the known bulb with the resistance of the candidate bulb.  The V=IR 
> part was a not very well thought out afterthought.  Sorry.  In any 
> event, I think we're overanalyzing this whole thing.  There are little 
> bulbs out there of appropriate voltage.  Try some and find one that 
> looks like it's the right brightness.  Done.
>
> -Steve
>
> At 04:56 PM 2/25/2008, Pat Horne wrote:
>> Steven,
>>
>> Cold resistance of a bulb is much lower than hot resistance. That's 
>> why most bulbs burn out when you turn them on.
>>
>> While it may not have an exact correlation, I just measured the cold 
>> resistance of a 130V 75W bulb and it measured 21 ohms. That would be 
>> 804 Watts cold filament dissipation. Using Ohms law, the resistance 
>> of a 130V 75W lamp will be 225 ohms hot, so you might be able to 
>> measure the resistance of another lamp and multiply the resistance by 
>> 10 to get hot resistance, but my measurements is just a sample of 
>> one. YMMV.
>>
>> Peace,
>> Pat
>
>
>


-- 
Pat Horne, Owner, Horne Systems 
(512) 797-7501 Voice		5026 FM 2001
Pat at HorneSystemsTx.com	Lockhart, TX 78644-4443
www.hornesystemstx.com
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