I need to control 12V/10W led brightness by a pwm signal. I know I can do it with an arduino and some TIP120 or another power transistor, but the question is, is there another method to generate a 95% PWM pulse without the need of an Arduino? And maybe regulate the duty cycle with a rheostat?
I'm doing this because of the big ammount heat dissipated by the led
Thanks everybody
Running the LED with pulses instead of DC won't reduce the heat the LED generates at the same brightness. In fact, it will make that a little worse.
You can run the LED dimmer than full brightness using pulses, and have the LED dissipate less power than at full brightness. However, just switching between 1/2 on and 1/2 off will give you close to 50% brightness, but will cause the LED to dissipate a little more power than if it were run steadily at 50% current. That is because the voltage drop across the LED is a bit higher at full current than at half current.
To actually do the switching controlled by a digital logic signal, the easiest is to use a "logic FET" low side switch. Something like the IRLML2502 can be driven directly from a 3.3 V or 5 V logic signal on its gate. Ground the source, and connect the LED between 12 V power and the drain.
Assuming you were going to use an Arduino Uno - see here for details https://www.arduino.cc/en/Main/arduinoBoardUno
You could use one of the 'PWM Digital I/O Pins' to generate a signal between 0 and 5V...
Let us call this your "control signal". You could then use this control signal with a transistor to drive an LED..
What kind of LED (specifically) are you trying to drive? If you provide the datasheet for the LED I think it will be much easier to help you out.
if the LED is 12 Volt (DC) and 10 Watt that implies a 1.2 Amp current!
If you are new to electronics - this is a good basic guide about LED control: https://learn.adafruit.com/all-about-leds/forward-voltage-and-kvl
