Which optocoupler and Mosfet for my project?

Using Arduino General Electronics
1

Hello,

Please have a look on the schema attached...

Which optocouplers and Mosfet should I choose?

Basically, I have :

  • 3 optocouplers (each of them is between the 5V from the Arduino and the 48V DC from the main supply)
  • 1 Mosfet for 3 LED branch
  • 2 Mosfet for 9 LED branches

Thanks for your support!

schema5.png
schema5.png1410×960 46.7 KB

2

I wouldn't use optocoupler at all. A Low Rds logic level MOSFET could sink current for 9 20mA branches in parallel easily if I understand you question correctly.

LED-MOSFET and 48V.jpg
LED-MOSFET and 48V.jpg1280×720 32.3 KB

3

Rate the MOSFET for 80 to 100V to be on the safe side.

The original circuit would simply burn out the MOSFETs immediately as there was nothing to
stop 48V hitting the gate.

4

Hi,
I'd have thought that keeping the old thread going would be preferred.

http://forum.arduino.cc/index.php?topic=389013.0

Tom... :slight_smile: