Sent from my Nexus 4 using Tapatalk 4 Beta. I have soldering skills. See my Luxeon Rebel Hydra-2 light: Email required Address never made public. Conveniently, 25 ohm, 5W resistors are widely available and inexpensive.
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Adding an optional 10K Ohm pullup resistor to the board, and some sort of inverting logic not on this board makes it compatible with the TLC The CAT is linear but if you pick your power supply within reason it is a good choice. Driving 3 white LEDs in series with just a resistor from 12 is verty effcient and there’s not much advantage in using a driver. Leed about 4W worst case but more likely around 1 or 2W. The eye light sensitivity is not linear but sort of logarymic http: Thank You in advance for any input Tom.
They come to me looking for a quick, simple answer. I don’t like to push the power ratings on resistors to the max, so I would suggest at least 4W resistor.
The need for the fan was marginal even with the heat sink as shown. After looking over the schematic, it would seem the vreg is only providing regulation for logic level. My experience is that contrary to theory, it will also vary with supply voltage, though that’s not an issue in the OP’s question.
As standard practice, I recommend lec series diode rated for a couple hundred volts, just to stop negative transient voltages. No one should use a dit law for a dimmer. This also means that the cost to build them are also lower.
Easy CAT LED Driver
Flashlights and Parts WTS: Leave a Reply Cancel reply Enter your comment here I will be driving these from a 12v dc source Wall Wart. The leftover 5 volts at say mA is 1.
I designed a few optional features into the schematic and PCB, purely for adaptability to different situations. This pin uses a small amount of power. But I want to build the driver myself because all the drivers I have seen online are expensive.
Simple 10 Watt LED driver is Hot Stuff | Hackaday
If I burn them up they are really cheap so who cares. I do have some 5v Wall Warts. In my job, the assumption is that a 12v battery can be anywhere between 9v and 18v. I might get a few of these and mess around with it.
Easy CAT4101 LED Driver
The final mounting is horizontal to mate up to the fiber optic whip from my scope. Two of the largest trade-off of not using a switching driver are efficiency and flexibility. And then there’s the issue of the voltage transients that can be on the battery bus!
You won’t find many drivers available cheaper. I bought cheapies to learn. When you hit the limit you effectively turn it into a constant current supply. I will need a driver to power a single led and a driver to power several in series.
My back of napkin calculations indicate about 3W on the higher side of things. The direction of the light also idy on the style of microscope ie; transmitted vs reflected light.
All oed are GMT After about a half hour the heat sink was very warm to the touch but not so hot it would hurt anything. Sent from my Nexus 4 using Tapatalk 4 Beta.