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#21
Archie, I will be learning about that stuff next year (EECE).
If by in series you mean the potentiometer connects to the LED, then yes.
I have the 12V in hooked up to the first 2 prongs of the pot, then the LED (with 500Ohm res) in parallel with the fan, both connected to the 3rd prong.
I know that they can be dimmed with lower voltage, but I think you are right, it is just not enough of a difference. At this point, I think I will be leaving the LED as is (it does SLIGHTLY dim, not noticeably), because the knob has as indicator arrow. I may even skip the LEDs for now as it doesn't quite fit with how I have everything laid out.
~Lordbob
Good find:
If you note my post above I showed how to dim LEDs. You need HE-LEDs to make it work, but the OP was looking for a simple way to just dim the LED with a POT, which is not going to work so I suggested a bulb. Replacing the LED with a simple RED bulb will make everything work without adding anything to his design.
The dimming link you provided: I don't think will work the way the OP wants it to. With a lot of LEDs it may sort of dim, remember LEDs are really an ON or OFF device, the graph on your link even shows that. (I would have to build circuit from your link and check how well it works) But using a transistor is not a very good way to dim the LED it will produce a lot of heat. Again pointing to the LED dimmer links I posted will dim the LEDs. It works by pulsing the LEDs with a 555 timer chip. Since we cannot see the LED turning ON and OFF the longer OFF time makes the LED look dim. I have built this circuit before many years ago and it does a good job, I would not say great because the LEDs will turn off at some point and they did not look very dim. Using the bulb makes the circuit simple without the need for the timer chip and extra space.
Great post, great options, let’s see which way LordBob goes.
excuse my reviving an old thread, but LEDS can be dimmed, and in the fassion LordBOB wants.
for proof, a quick experiment, get one of the POTS, and a cheapo LED FAN from somewhere (That connects VIA molex 12v)
watch how the three LEDS dim when you turn the POT down, and brighten as you turn it up.
Maybe (this might be a slight messy, but) you could take one of those cheapo fans, fit it, put an extention on one of the three LEDS, and put that up front of the case? - dimming LED
or put all three leds up front and use them to surround the knob?
phunky