I originally sent this post as an email question / suggestion and it was suggested I post it in the forums.
The FemtoBuck is AWESOME! However, I need a 1A (or 1050mA) Constant Current Regulator. I know the device can be modified by replacing one of the 0.3ohm resistors with a 0.1ohm resistor to attain this, but it’s too tricky (small) for me to make the alteration in my garage, those resistors are tiny. Since the FemtoBuck is currently backordered, and SparkFun is producing 1500+ more, why not make several capable of the full 1A? Perhaps a couple of 0.2ohm resistors (bridged to allow 0.1ohm), rather than the pair of 0.3ohms? That would offer a 500mA and 1A version. As a follow up question, how much would it cost to custom order some 1A units described above, and what’s the minimum order? Many thanks, and keep up the good work!
Any ideas? Opinions?
Hi, and thanks for posting!
Sadly we can’t do a custom run on these, we just don’t have the needed parts in stock and due to COVID restrictions we don’t have the manpower.
But, don’t let the small size of those resistors scare you, here’s a tip for adding a third resistor.
- First you need a resistor, [Digi-Key has them here.
- Once you have a resistor put a [u]tiny, tiny[/u] drop of superglue on the bottom of the resistor using the pointed end of a toothpick. What you're looking for is just enough glue to hold the resistor in place without getting glue on the conductive metal ends. (A pair of tweezers is recommended for this part.)
- When the glue dries, just solder the ends of the resistors together one at a time and also close the jumper on the board.
Once you’ve done that, the combined resistance of all three resistors in parallel will be the 0.1 ohms you’re looking for.](CRL0805-FW-R300ELF Bourns Inc. | Resistors | DigiKey)
That’s a clever idea, I’ll certainly give it a try. Thanks for the tip!