Hi, my first post here so please be gentle, i am an Electrical Engineer but Electronics have never been my strong point, although i trying to improve that.
I have some RGB 3-colour LEDs (low-power), 4pin with Common-Cathode and i am trying to get a basic circuit allowing me to dim each colour separately and thus mix many different colours from the one led. Eventually i hope to use PIC's for this, but right now i havent got those here. So i built a simple dimmer with a 555 chip as below (only 1 led not 3 though):
Now being a novice at Electronics i figured if i make 3 of these circuits i could then control each of the 3 colours individually, however i think the "Common-Cathode" is making this not work. As i have made the 3 circuits and connected it to the led on a breadboard (bit messy) and when i adjust any of the 3 Pots, the 3 colours together dim etc, they are not controlling each colour separately but all together on any of the 3 circuits.
I assume this is because the dimming is being done on the common-cathode and therefore instead of dimming each colour, its dimming the whole set of colours in unison.
How if at all can i convert this circuit to dim each of the 3 colours individually please? Without using any PICs etc yet. All i have here right now is 3 555's and a mass of resistors/caps/diodes etc
Thanks and hoping in advance......
I have some RGB 3-colour LEDs (low-power), 4pin with Common-Cathode and i am trying to get a basic circuit allowing me to dim each colour separately and thus mix many different colours from the one led. Eventually i hope to use PIC's for this, but right now i havent got those here. So i built a simple dimmer with a 555 chip as below (only 1 led not 3 though):
Now being a novice at Electronics i figured if i make 3 of these circuits i could then control each of the 3 colours individually, however i think the "Common-Cathode" is making this not work. As i have made the 3 circuits and connected it to the led on a breadboard (bit messy) and when i adjust any of the 3 Pots, the 3 colours together dim etc, they are not controlling each colour separately but all together on any of the 3 circuits.
I assume this is because the dimming is being done on the common-cathode and therefore instead of dimming each colour, its dimming the whole set of colours in unison.
How if at all can i convert this circuit to dim each of the 3 colours individually please? Without using any PICs etc yet. All i have here right now is 3 555's and a mass of resistors/caps/diodes etc
Thanks and hoping in advance......