74HC4051 use problem

Engineer asked Apr 27,2022

Using 74HC4051, the eight inputs are connected together to a sine signal (only for testing so the inputs are connected together), and the sine signal measured at the output is as shown in the figure, the waveform is very wide, about 200mv. And when measured with an oscilloscope pen, it sometimes turns into a normal waveform by itself as shown in the figure below

The above phenomenon feels like a chance event, which happens occasionally.

And the experiment before obviously did not have this phenomenon, it was always a normal waveform. I added a bypass capacitor coupling capacitor to the op-amp in other parts of the circuit, and then it became like this.

Does anyone know what is the reason for this?


  • Your Answer(3)
You can only upload 1 files in total. Each file cannot exceed 2MB. Supports JPG, JPEG, GIF, PNG, BMP

Your professional answers would kindly help others and you will get a reward with PCBWay Beans.

    View More
    Browse other questions tagged or ask your own question.
    Ranking Name Answers
    1 Cook 3
    2 PCBWay Support 2