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Topic: Clean and energy efficient LED dimming (Read 4 times) previous topic - next topic


Hm, a resistor at the gate? I have the 4.5Volt at the LED even with the gate not connected to the Arduino.

To test. disconnect from the Arduino and tie the gate to ground using your pull-down resistor. You can short it to ground if you like. Check if you still have 4.5V

Source voltage? You mean the 12Volt that go to the LED? The IRLU8726PBF is made for up to 30Volt.

Sorry, that is fine, what I meant was do you have the correct limiting resistor for your LED for the voltage being supplied?

Are your grounds okay? Short, connected to a single point. Is your CAT6 shielded? and if so, is the grounding at a single point - it's not unusual for Radio2 to take control of your circuit ;) If you have wires spanning the house, you will have quite a nice antennae going. Look out for the WOW! signal ;)
For whom does the clock pulse? It pulses for you!


Feb 15, 2013, 03:57 am Last Edit: Feb 15, 2013, 04:37 am by MrGlasspoole Reason: 1
Grounding the gate changes nothing.
There is no limiting resistor cause its a 12V LED. Its one of those you can swap with
the 12V halogen lamps in halogen systems: http://www.amazon.de/ersetzt-35Watt-Halogen-warmes-Kelvin/dp/B0076J5AHG/
They are really bright like 35Watt normal lamps and make a nice light.
The first LED i saw that really make sense when it comes to price<->power saving (amortization).

There is no CAT6 at the moment. Everything is short and on the breadboard :D

But when you talk about shielding. Would you always connect the shield to ground?
Both ends ore just one?
I use just shielded cable:
Stranded CAT.5E SF/UTP for switches and flow sensors.
Stranded CAT.6 S/STP for network.
Solid CAT.6 S/FTP AWG23 for 12V power to the LEDs and Arduinos.
Lappkabel UNITRONIC LiYCY 2x0,25mm2 where i have to spread the 12V: http://products.lappgroup.com/online-catalogue/data-communication-systems/low-frequency-data-transmission-cables/din-colour-code/unitronic-liycy.html

And i want to make a extra cable from the breaker box to my home stereo.
I want to use Lappkabel ÖLFLEX 120 CH 3x2,5mm2: http://products.lappgroup.com/online-catalogue/power-and-control-cables/various-applications/halogen-free/oelflex-120-ch.html
But i'm not sure what to to with the shield on this 220Volt cable.


I'm no expert, but since MR16 lamps are designed to be compatible with halogen lamps their internal circuitry, by design, has to work in concert with transformers and dimmers made for halogen lamps. This compatibility requirement has led to proprietary solutions which may have important side-effects.

I'm not sure whether the source can be considered reliable, but here's a couple of articles that worried me
http://ledsmagazine.com/features/9/6/8 and http://ledsmagazine.com/features/9/2/10.


Feb 15, 2013, 09:27 am Last Edit: Feb 15, 2013, 09:40 am by MrGlasspoole Reason: 1
God damn. After removing the LED i still had 12Volt.
From 10 Mosfets i picket a broken one :0

So i did some testing now and the electronic in the LED makes problems.
Here are some measurement:
Monitor PWM: 1, Pin 6 Volts: 0.03
D6 = 0.02 Volt
LED = 0.00 Volt (lights up)
LED turned = 0.21 Volt (lights up)
no LED = 11.3 Volt

Monitor PWM: 36, Pin 6 Volts: 0.72
D6 = 0.71 Volt
LED = 2.85 Volt (lights up)
LED turned = 2.85 Volt (lights up)
no LED = 11.5 Volt

If i connect the LED directly to the 12 Volt power supply i have 12 Volt at the LED.
In the PWM circuit i have the funniest volts.

There are allot PWM circuits out there but PWM is what the Arduino does.
Maybe a LED driver?
I found this: http://www.led-treiber.de/html/leds_grundlagen.html#PWM-Dimmer
and they write it works with all there LED drivers: http://www.led-treiber.de/html/getaktete_treiber.html

How about a power supply for all the LEDs and a "reverse phase control dimmer" in front of them
who is controllable with the Arduino?

There must be a way to dim those LEDs with some kind of circuit :-(


Feb 15, 2013, 09:48 am Last Edit: Feb 15, 2013, 09:51 am by lax123 Reason: 1
your link to your LED:

"Produktmerkmale: Nicht Dimmbar", cant be dimmed

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