My take on Noise Free, Flicker Free LED Light for Electronics Work bench - Page 1
Forum section: electronics / general

author: RoadRunner
author_rank: Frequent Contributor
timestamp: December 14, 2024, 06:01:55 pm
content: This my short video about using a Supply to have Noise freem flicker free LED light for work bench.Do you happen to know if there any other way to achieve similar results?

author: jonovid
author_rank: Super Contributor
timestamp: December 14, 2024, 07:38:32 pm
content: any iron core transformer with a DC linear regulator power supply and any LED strip lights that do Not have buck boost converters or switching regulators.try recycling / repurposing the cool white LED strip lights found in the back of old liquid-crystal-display televisions will do the job.the plastic lighting diffuser sheet can also be repurposed from the LCD tv and cut into strips for your LED strip lights.

author: amyk
author_rank: Super Contributor
timestamp: December 15, 2024, 09:07:04 pm
content: Capacitive dropper or linear regulator with a big enough reservoir capacitor after the regulator will work.

author: Kean
author_rank: Unknown
timestamp: January 11, 2025, 02:22:32 pm
content: The addition of the Traco for isolated 5V means it isn't a purely linear solution, but at least the Traco should be pretty low noise and the dimming is linear. Good solution overall.I've been planning something similar for when I build new shelving above my workbenches. My plan is to have a general 12V power bus that runs the LEDs and is available for other devices. There will be multiple LED strips maybe 300mm long with individual linear dimmers to spread out the thermal load, and multiple analog dimming signals to allow brightness control in zones.Maybe later the analog dimming signals will be linked into some central automation, but while I design lighting controls for clients I have little interest in having it in my own office. I guess some simple motion based control could be handy.

author: Marco
author_rank: Super Contributor
timestamp: January 12, 2025, 01:32:10 am
content: Is it really worth worrying about non dimmable LED lighting with linear regulators? It's just another rectifier bridge and linear regulator to join all the other ones.

author: ledtester
author_rank: Super Contributor
timestamp: January 12, 2025, 03:49:12 am
content: I took some time to investigate this design...The board is powered by a 19V laptop power supply:https://youtu.be/Z3r2z976tUc&t=5m55sBut he needs 24V to power the LEDs:https://youtu.be/Z3r2z976tUc&t=10m38sSo that's why the Traco is there - to add an extra 5V to the output of the laptop supply:https://youtu.be/Z3r2z976tUc&t=11m10sand also to power the fan.Btw, the LED PCBs were custom made:https://youtu.be/Z3r2z976tUc&t=9m10sso maybe using the Traco (which definitely costs more than $5) could have been avoided by putting fewer LEDs in series.The last curiosity about this design is that the power supply definitely one of those 2ma-3A, 30V boards that has been widely discussed here. But I recalled that relies on an AC supply in order to generate the negative rail. In fact, it doesn't work when powered by a DC supply:VoltLog #8 - Kit Assembly 0-30V 0-3A Adjustable Linear Bench Power Supplyhttps://youtu.be/L2X6bAfmBno?t=14m50sBut then I learned that this can be worked around by not populating the transistor which detects when the negative rail collapses:https://youtu.be/L2X6bAfmBno?t=17m50sUsing the schematic-PCB correspondence at:https://www.paulvdiyblogs.net/2015/05/tuning-030v-dc-with-03a-psu-diy-kit.htmlyou can indeed tell that transistor Q1 has not been populated (see attached photo).Blog write-up:https://www.circuitvalley.com/2024/12/low-noise-electronics-bench-led-light-linear-supply-5dollar.html.html