Hello people. i'm new to this forum and this is my first post I need to drive an optocoupler from my motorcycle's battery. Battery voltage is 12 to 14.4, depending on the engine revs. can i drive the optocoupler with this voltage? Or do i need to limit the voltage? The optocoupler's output will only light up a 3v LED. which optocoupler should i use? 4n25?

Thank you

 

the voltage is ok but you must limit the input current to a safe value no more then 10ma safety and the output also to no more then 20 ma asume 14.4v need Ω1.0k input output 560Ω add a diode to the input anode to gnd breakdown is only 2v and this is for a 2n24 2n25 maybe better but i have no spec for it.
good luck

 

Hello to all. I need a circuit with a optocouple to switch a relay. The input that I need is 12V and the relay is 12V too. I 'll like to use like a simple relay. Do you pls tell me what resistance must choose and what optocoupler is good to make this circuit. Thanks

 

Why are you using an opto-coupler? What are you trying to do?