Here is my situation I have a few RGB LED's
Found here **broken link removed**
This unit uses a common anode (+) with a lead for each to activate each color to ground. The problem it I have positive voltage as a signal for each leg when I should have a ground signal to illuminate the LED. I figure the easiest way to attack this is with a NPN switching transistor (I think a small relay per leg would be overkill) the problem is I am a total NOOB when it comes to transistors! I read the "Transistors Explained" FAQ and have learned that I need at least .7v to the base of the chip. (can I just use 3v to the base when the collector is connected Gnd and the emitter is connected to one of the multiple cathodes of the LED… This sure would make things easy) if not what the heck resister should I use to get a perfect .7v base signal out of my 3v? How about 5? Am I going about solving this problem the right way?
I consider myself to be a fairly intelligent individual but Ohms law always seems to elude me… lol all I need to lean is how to choose the right resister to attain a needed voltage. I just don’t get it! But that is another story Thankyou kindly in advance for any help I get here.
Found here **broken link removed**
This unit uses a common anode (+) with a lead for each to activate each color to ground. The problem it I have positive voltage as a signal for each leg when I should have a ground signal to illuminate the LED. I figure the easiest way to attack this is with a NPN switching transistor (I think a small relay per leg would be overkill) the problem is I am a total NOOB when it comes to transistors! I read the "Transistors Explained" FAQ and have learned that I need at least .7v to the base of the chip. (can I just use 3v to the base when the collector is connected Gnd and the emitter is connected to one of the multiple cathodes of the LED… This sure would make things easy) if not what the heck resister should I use to get a perfect .7v base signal out of my 3v? How about 5? Am I going about solving this problem the right way?
I consider myself to be a fairly intelligent individual but Ohms law always seems to elude me… lol all I need to lean is how to choose the right resister to attain a needed voltage. I just don’t get it! But that is another story Thankyou kindly in advance for any help I get here.