I need a circuit that makes 15 green LEDs fade slowly in and out every 30 seconds. I also need to know what batery this will need for it to run for 2 hours.
As I said in your previous post 15 Leds at 20mA will be :
Iav = 50% *20mA * 15 = 150mA, using three AA batteries this circuit can last above and beyond 2 hours. 150mA * 2 hours = 300mA hours.
P = IV
Pav = 50%IV *15 Leds
Pav = 0.5 * 20mA * 3V * 15V
Pav = 0.45W
Now you need to account for the power dissipated in the resistors etc.
Thank you two for the reviews, I have not been able to change any errors, though, It wontlet me on the sie! But please stick to he circuit. I only have 3 days left to gt it! can someone please post a schematic!!! It just needs to make the LEDs fade in and out.