Use the reference schematic below.
Pin No.5(signal INPUT) is OPEN.
But LED is lights up.
Please tell me the reason and how to improve.
This thread has been locked.
If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.
Input signal at pin 5 is not supposed to be left floating/open and it should always be driven with a voltage level. This is a high impedance input and if left floating, any noise/residual signal has the potential to cause erratic behavior of the LEDs.