Hi All,
Tried to find my answer among previous threads, Mr. Marsden blog and various other websites. Hours of time and research in my first attempt to build a simple PWM circuit to dim some LED's for my aquarium moon light.
I am wanting to power 12 5mm blue leds over my aquarium for accent/moon lights. Each LED has a fw voltage of 3.5vmin-4vmax and a fw current of 20mA. I was planning on wiring 4 sets of 3 in series using a 12v ps and 75ohm 1/8w resistor.
I've located a schematic that shows exactly what i want to build but the output is 10v not 12v. It's using a lm317 regulator(with resistors) to step down the voltage. If i have a 12v regulated ps that will output 12.05v-12.3v +-3% could i just exclude the lm317 and resistors? should I swap out the lm317 for a fixed regulator like a L7812? Should I get a 15v(+) ps and change the resistors?
I think all would work but what is the best/reliable/efficient way to go about this?
Tried to find my answer among previous threads, Mr. Marsden blog and various other websites. Hours of time and research in my first attempt to build a simple PWM circuit to dim some LED's for my aquarium moon light.
I am wanting to power 12 5mm blue leds over my aquarium for accent/moon lights. Each LED has a fw voltage of 3.5vmin-4vmax and a fw current of 20mA. I was planning on wiring 4 sets of 3 in series using a 12v ps and 75ohm 1/8w resistor.
I've located a schematic that shows exactly what i want to build but the output is 10v not 12v. It's using a lm317 regulator(with resistors) to step down the voltage. If i have a 12v regulated ps that will output 12.05v-12.3v +-3% could i just exclude the lm317 and resistors? should I swap out the lm317 for a fixed regulator like a L7812? Should I get a 15v(+) ps and change the resistors?
I think all would work but what is the best/reliable/efficient way to go about this?