NOTICE: This webpage and associated files is provided for reference only. This is not a kit site! It is a collection of my work here at the University of Toronto in the Physics department. If you are considering using any schematics, designs, or anything else from here then be warned that you had better know something of what you are about to do. No design is guaranteed in any way, including workable schematic, board layout, HDL code, embedded software, user software, component selection, documentation, webpages, or anything.
All that said, if it says here it works then for me it worked. To make the project work may have involved undocumented additions, changes, deletions, tweaks, tunings, alterations, modifications, adjustments, waving of a wand while wearing a pointy black hat, appeals to electron deities and just plain doing whatever it takes to make the project work.
Each of the ten identical constant current circuits uses an opamp to compare the LED current through a 1 Ohm resistor to a setpoint from a pot. The pot, common to all ten circuits, is driven by a 1.25V band-gap regulator which in turn is enabled by an opto-coupled TTL input. The pot is a trimpot and needs a screwdriver to adjust it so that it cannot be accidentally changed.
|Sorry, no more chance for asking direct questions, queries, broken links, problems, flak, slings, arrows, kudos, criticism, comments, brickbats, corrections or suggestions.|