When the frequency of rotation of disc matches that of led blinking frequency..
the disc appears to be stationary to human eye(persistence of vision.
Actually using a pot to vary the frequency of 555 in astable mode
Thats why it appears to move back and forth while tuning.
But once tuned,it appears to be solidly stationary disc!!
Please like the video if u like it!
Comments/suggestions welcomed!
![](https://i.ytimg.com/vi/d23IGrmkph4/mqdefault.jpg)