Re: [IRCA] noise issue update

[Tim Hills <thills@xxxxxxxxxxxxx>]

Old trick on that one, making filaments last longer that is.

A diode in series with the center conductor drops the wattage of a 100W 
bulb to about 82W and they last many times longer. Tungsten increases in 
resistance as it gets hotter so even though the RMS voltage is 1/2, the 
current is higher making up the other 32% of power. Learned that trick 
when I worked for 3M on overhead projectors and copiers (ahem)  a few 
years back.

2A 400V diodes are fine for up to 100W, increase the current rating for 
larger bulbs.

Center conductor on an Edison base bulb because the outer screw-ring is 
(supposed to be) neutral with the center being hot. Safety first.......

A 0.1 uF 400V ceramic cap  across the diode should kill any RFI.

0.01uF/1KV  caps across the ballast of fourescents also kills the noise 
nicely but only on the transformer based ballasts.

On 6/28/2011 14:18, Patrick Martin wrote:
> I heard the old bulbs will not be sold past 2018 here, except the odd
> sizes. But the 40-60-75-100w units will be history. But I still have 6
> or 7 years to stock up more. Home Depot has good prices on them, plus
> the Dollar stores, 4 bulbs for a dollar there. I have tryed the
> expensive bulbs and the inexpensive and they all seem to last about the
> same. What helps I have heard if to limit to voltage/urrent, they last
> longer.
> Patrick
>
> Patrick Martin
> Seaside OR
> KGED QSL Manager
>
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