could i connect 12v to LED?

[cpteoh26]

led 12v resistor

well, a quick question,
could i connect 12v to a LED?
i will use resistor to limit current to 25mA, but just wondering would LED could accept 12V?
or it will kill the LED?

thanks

 

[FvM]

12v led resistor

If conncted with correct polarity, the diode voltage is self limiting (if a suitable resistor is present), but reverse polarity would immediately destroy the LED. If there is any risk of wrong supply polarity, you should connect a diode, either in forward series connection or in reversed antiparallel connection to the LED.

P.S.: You can also use a two pin bi-color diode, it shows different color with reversed supply, but is effectively protected.

 

[pauloynski]

12v resistor

By placing a limiter resistor in series the voltage drop across the resistor will bring the voltage across the led to its nominal value. Leds are current driven, not voltage driven. No problem in doing that with a resistor. The value should be near 470Ω or 680Ω.

 

[cpteoh26]

resistor for led 12v

If conncted with correct polarity, the diode voltage is self limiting (if a suitable resistor is present), but reverse polarity would immediately destroy the LED. If there is any risk of wrong supply polarity, you should connect a diode, either in forward series connection or in reversed antiparallel connection to the LED.

no wrong polarity risk for my case.
therefore, just double confirm, i could just connect directly 12V to my led. to limit current to 25mA, i will need to add a 480Ohm resistor in series with the LED.

am i correct?
thanks.

Added after 2 minutes:

thanks bro FvM and pauloynski
i got the point.
now i could proceed with my project. thanks for fast reply.

 

[pauloynski]

connect led 12v

Yes, just confirm that 25mA is the right current for you led. Also, note that depending on the led color the voltage across it is slightly different. Red=1,9V, Green = 2,3V and Blue = 3,6V (may differ depending on the brand and current). The value you´ve choosen seems to be safe for all types.

 

[pel155]

how to connect led in series

Yes.. you have connect

+12V -> resistor 380 to 560 Ohm -> Diode - > GND

Is't necessary exactly 25mA, the LEDs turn on with 8mA to 30mA without problems

 

[stanislavb]

connecting leds in series

Hey,
What you wrote before was correct. Choosing resistor you should remember about power dissipation on it. I don't know what is the LED you picked up. Suppose drop in voltage on LED is 1.4V. (12-1.4)*24mA=0.25W. So you have to choose current limit resistor which is capable dissipate 0.25W.

 

[car19]

how to connect resistor to led

For a LE to work from 12 volts I have been using a 1K to be on the safe side and I have been running a LE of 12 volts AC for over 4 years works well after all ;all that we are doing is converting AC to DC

 

[gaurav_sharma132]

led resistor 12v

No cpteoh26, you can not connect led to 12V directly as it simply burns out.

You have to put resistor in series....

To calculate it....R=(VI-VF)/I

where VI=input voltage which is 12V in your case
VF=forward voltage
I=current drawn by led which is usually 25-30 mA

Hope it helps you !!

 

[ehico16]

connecting led in series

try to use 3 white led in series parrallel as many the battery can carry since white led work from 3v to 4v