Leds Dimming or Lower voltage? - Electronic Circuits Projects Diagrams Free

vinvin · 26th September 2006, 02:02 AM

Hi,
I came across a circuit today and i saw some dimming leds sequences.
Its like it fades off rather than turns off straight away..

When i take a closer look, it uses a PIC16F628A.
The circuit is relatively simple it uses MOSFETs.

Is there a way to write the program as such??
Variable output voltage??

Thx in advance..

kchriste · 26th September 2006, 03:21 AM

The PIC just uses PWM to dim the LEDs. It just varies the duty cycle of a squarewave to change the LED brightness. The square wave is of a high enough freqency that your eyes don't see the flicker.

vinvin · 28th September 2006, 04:49 AM

Thx for the explaination..
Btw do u have some code sample that i can refer to?
and wats PWM?

**Nigel Goodwin** · 28th September 2006, 07:58 AM

Quote:

Originally Posted by vinvin

and wats PWM?

If you ask google I'm sure you'd find out, but it's Pulse Width Modulation.

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26th September 2006, 02:02 AM	(permalink)
vinvin	Leds Dimming or Lower voltage? Hi, I came across a circuit today and i saw some dimming leds sequences. Its like it fades off rather than turns off straight away.. When i take a closer look, it uses a PIC16F628A. The circuit is relatively simple it uses MOSFETs. Is there a way to write the program as such?? Variable output voltage?? Thx in advance..

26th September 2006, 03:21 AM	(permalink)
kchriste	The PIC just uses PWM to dim the LEDs. It just varies the duty cycle of a squarewave to change the LED brightness. The square wave is of a high enough freqency that your eyes don't see the flicker. __________________ --- The days of the digital watch are numbered. ---

28th September 2006, 04:49 AM	(permalink)
vinvin	Thx for the explaination.. Btw do u have some code sample that i can refer to? and wats PWM?