Control a 12V LED

[pssf84]

Hi,

I need to control a 12V LED that is inside a button. I know I can do it with a relay, but wanted to avoid the physical sound of it, can I do it with mosfets? How? Can I use the irlz34n ?

[scotty101]

Can I use the irlz34n ?

Yes. A MOSFET will do the job and this specific one will also work with the logic levels output by the pi's GPIO pins.

See https://www.raspberrypi.org/forums/view ... p?t=175032

[neilgl]

Does the LED inside the switch already have a resistor ? - some you have to add an external resistor to run at 12V (LED is usually around 3V)

[pssf84]

Can I use the irlz34n ?

Yes. A MOSFET will do the job and this specific one will also work with the logic levels output by the pi's GPIO pins.

See https://www.raspberrypi.org/forums/view ... p?t=175032

So I think it should be something like GPIO 3.3V to MOSFET G, ground to MOSFET S and 12v to LED + and LED - to MOSFET D ? Is this correct ? Cannot opne button to see if LED has a resistor, it's a push button with a led inside.

Do I need to use diodes?

[neilgl]

Do you already have the MOSFET - it is rated at 30Amps but you only need 20mA to drive an LED, so it is an expensive option?

[pssf84]

Do you already have the MOSFET - it is rated at 30Amps but you only need 20mA to drive an LED, so it is an expensive option?

I already have the MOSFETS irlz34n. Why is an expensive option? How to make it cheaper? But can it be done? Would I need diodes as well? If yes, what kind of diode? any greater than 12V ?

I am controling the 12V LED now by relay, but I want to avoid the physical sound of it...

[LesniakM]

Maybe 2n2222 transistor? It handles up to 65V/600mA if I remember correctly(anyway, for sure it will handle ur diode) and still can be activated by Raspi, so would be suitable for this, any maybe many more applications in the future.
Moreover very cheap and extremlly popular around the world.

[drgeoff]

Diode not required for switching a LED.

I would advise adding a resistor between MOSFET gate and ground. Value not critical. Anything between about 10K and 100K.

[pssf84]

So something like this?


https://imgur.com/WCrsISk.png


And if I need to add a 12V fan ? same thing done for 12V LEDs but with diodes?

[jamesh]

Continued here https://www.raspberrypi.org/forums/view ... 1&t=248308