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AC Powered White LED Circular Magnifier Work Lamp

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Step 7: Layout of the new lamp

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Tape the nice surface of the white board with masking tape to protect from scratches during all the handling required and to provide a surface to draw on. It also helps keep the cutting and drilling neat.

Remember to measure twice and cut once.

A large circle-drawing compass is most handy in laying out the project. Cut the white board piece to a round circle of a diameter just less than the diameter of the light head, my circle was 8.7 inches (221mm). Band saws work great for this, but a scroll saw will work as well.

Layout and draw the inner circle just larger than the lens; do not cut this out until the holes are drilled. I was able to insert my circle partway and used the open lens hole to trace a draft circle. Then I corrected the trace to make this circle a bit larger. My circle was 5.2 inches (132mm).

Ok, here is the tough part. You need to draw the four equally spaced circles that the LED's will be aligned on, then divide the circles evenly depending on how many LEDs you use. Since I decided to make my light strings 2 sets of 30 LEDs in series with each set of 30 consisting of 2 strings of 15 LEDs in series. I needed to divide each of my 4 circles into 15 equal sections. I found that my circles were too close to fit the jumbo LEDs perpendicular to the circles. I tried to get fancy with a spiral effect. Now go do it.

To make it easy to layout the 2 holes per LED I then used a small circle (same diameter as the LED legs are wide) to speed layout.

 
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rgbphil6 years ago
Great idea, I've just gone through replacing my ring flouro on my own magnifier lamp. Couple of points though....I presume you meant your configuration is 2 sets of 30 LEDs, in parrallel with each set consisting of 2 strings of 15 LEDs in series?? I'm trying to figure out how you could get 60 LEDs in series going on 120VAC, the combined forward voltage for 60LEDs would be around 192V (assuming a forward voltage of 3.2V per LED). Could you add a cct diagram showing the electrical connections? Concerning the 120VAC supply, I'd recommend another warning that when adjusting the beam of the LEDs, that the ring will be at mains voltage.
arcticpenguin (author)  rgbphil6 years ago
rgbphil, Thanks for your comments. At the bottom of Step 2 I've included a pdf file that is the schematics. I tried doing up a pix of it but the text is not clear enough. Once you see the pdf you'll see the circuit is rather simple. That with article I quoted will explain the theory better. When adjusting the beam of LEDs the ring is at Mains voltage but no exposed metal is present, it is all taped and insulated behind the whiteboard. Thanks
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