Hi Pedro,

If you want to run the 16 LED's at 30 mA each, your 12V power supply

must have at least 500 mA (16 X 30 mA=480 mA) or better capability.

A power supply with 1A capability would run much cooler. Each of the

LED's, if they don't already have a built-in resistor, will need a

series limiting resistor to insure your 30 mA of current is not

exceeded. The forward voltage (VF)drop is not mentioned in your spec,

but the LED's are probably dropping about 2 V, that would mean that

you have about 10 V dropped across your

limiting resistors. Using Ohms Law R = E/I you can calculate the

resistor value to be R = 10V/.03A = 333 ohms. Resistors come in

standard values, the closest value for the above application is a 330

ohm. The power rating of the resistor can be found by using the

formula P = E X I, in this example P = 10V X .03A = 300 milliwatts.

Therefore the 330 ohm resistors should have a power rating of at

least .5 watts (500 milliwatts). If you are desiring to have all 16

LEDs on at the same time, connect each of the LEDs with their

respective resistors in series and then all of them across the 12 V

source. Insure that the polarity is such, that the LED's are forward

biased, negative through the series resistors to the cathodes, and

positive voltage to the anodes. Hope this helps.

John

--- In Electronics_101@y..., "Pedro de-Oliveira" <olive_@h...> wrote:

> Hi all

>

> I am a newbie to the art of electronics so please be gentle with

me :-)

>

> I am trying to run 16 LED's from a single 12v power source. The

LED specs

> are as follows:

>

> Parameter Value Units

> DC Forward Current[1] 30 mA

> Peak Forward Current 100 mA

> Average Forward Current 30 mA

> Power Dissipation 120 mW

> Reverse Voltage (IR = 100 mA) 5 V

> LED Junction Temperature 100 °C

> Operating Temperature Range 40 to +80 °C

> Storage Temperature Range 40 to +100 °C

>

> What I would like to know is what would be the best way to hook

these things

> up and what value resistors I would need to do it.

>

> Cheers

> Pedro

>

>

>

> _________________________________________________________________

> Get your FREE download of MSN Explorer at

http://explorer.msn.com/intl.asp