How to wire a photocoupler 4-channel 5kvrms 16-pin dip liteon ltv-847? Particularly, which side is input and which is output.
The datasheet tells you such things. The side with the dot has the LEDs, the other side is for the photo transistors.
Do photocouplers put out data as if it was a photoresistor or is it only designed to say if it's high or low?
As the components are LEDs and phototransistors you can transfer analog values but most of them are designed to be used in digital environments (you would have to calibrate each if you use them otherwise), types that can be used for analog transfers are usually marked accordingly.