62. Optocoupler Circuit Design

Question.5

Hardware developer wants to monitor noisy 24v DC industry signal High & Low. So he did the following connection. However controller failed to detect signal properly.

What is the issue in the circuit?

Need Help? Refer to the Quick Guide below

Select Answer

Reverse connection of Optocoupler.
Missing pull-up resistor on output side
Missing Resistor between GPIO and collector pin
Emitter should be connected to GPIO Pin.