Simple Circuit Reduce Voltage 10v to 3v

[beehub21]

Hi all...

How to reduce voltage output from 10.5v to 3v and 1.5v?
i can't put LED Light 3v and 1.5v to my transformer 10.5v thats why...

what resistor that i need. and also how to increase a 10.5v output to12v output?
i want my 10.5v supply make 12v same as my blower 12.

anyone can help me this? please send me a simple diagram for this circuit thanks..

[hailrazer]

You wouldn't use a resistor you would use a regulator.

The Ti chip is one of the best. You can change the value of the resistor used with the Ti chip to get 3v and 1.5v

It is the PTH08000

[nevermind1534]

If it's just a few LEDs, you could use a resistor.

[beehub21]

I MEAN what size and wattage of resistor that i need to reduce the 10.5v

[low_budget]

Use ohm's law.

E
----
I | R

E= volts
I = amps
R= ohms

you need to know the voltage and amperage requirement for the led
say the led is 3v and 20mA

10.5v - 3v = resistor voltage drop
if the led uses .020 A, the resistor will use same amps (wired in series.)

7.5v divided by .020 A means you need a 375 ohm resistor

If you need further explanation perhaps google it, basic electronics

[jdmlight]

Or be lazy and go here: http://ledcalc.com/
(an online calculator which uses the math that low_budget just explained)