First posting here.
I am using PC817 opto coupler( about How Optocoupler Works and the Optocoupler Basics http://www.apogeeweb.net/article/69.html). I want a 3.3 output voltage. In its 1st pin I am giving 12volt and 2nd pin is gnd. I have connected a pull down resistor on 3rd pin. But i am confused because when I am giving 3.3volt on 4th pin, and I am checking output from 3rd pin which is 1.5volt. How can I get 3.0 - 3.3volt output on 3rd pin.
I have tested it with 5 volt, means when I was giving 5 volt on 4th pin and when I was checking voltage on 3rd pin it was 4.7-4.8v which is I think correct. But I dont know what is happening in case of 3.3volt. PLease help.
EDIT : i have attached a screenshot of proteus simulation. I actually didnt find the PC817 opto coupler but I got the similar opto coupler. I am getting an output voltage of 3.22. Please tell me that is this connection good. I mean if I make this connection in real, will this work?