On 3/30/2018 10:54 AM, Jim Stahl via RFI wrote:
Is 12 volts DC a common or standard low voltage level? What is the approximate
DC current per bulb, i.e. if I were to replace the RFI generating switching
supply with a linear supply, how big of a supply would normally be needed?
I can answer part of this. I'm lighting my shack with five strips of
LEDs powered from the shack's 12V system (a float-charged Costco deep
discharge battery). Together they draw about 1.2A I have two of these
strips mounted behind me on a room divider to illuminate my computer
desk for reading print. They're fed by a linear wart rated 12V/500mA,
and the wart is barely warm to the touch.
https://www.wiredco.com/LED_Strip_Light_12_Volts_SMT_Cool_White_20_p/ledbar1.htm
https://www.wiredco.com/LED_Lighting_Low_Voltage_s/1874.htm
This company has been at west coast hamfests for at least 5 years. In
general, their electronics stuff is crap (noisy SMPS, a USB FM modulator
that spews noise sidebands, crummy knock-off connectors and patch
cables), but the lighting that doesn't include power supplies is very nice.
And this observation. Depending on how dimming is accomplished, it could
also be adding noise to what the SMPS is producing. My guess is that
you'll need ferrite chokes on wiring between the PSU and the AC line.
The good news is that the current is quite low, especially on the 120V
side, so small conductors on small cores can be used. If you're going to
build something to fit inside an existing fixture, be sure to use wire
with insulation rated for use on AC mains.
If you would like some design help with chokes, shoot me a private email
and we can talk about it.
73, Jim K9YC
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