Seen this in many houses, people upgrade their lighting setup and install a dimmer. Which works. But usually it also makes the lights flicker unintentionally, which is super annoying IMO.
Now, my understanding of electrical engineering is pretty rudimentary so I’d appreciate more something that explains the concept in a way that Cavewoman Mothra can understand rather than something technically accurate.
Thanks
Building on their comment, perhaps the capacitor is building up energy and dissipates it every 20 seconds. Like beats in resonance when you hear a pulsing in the volume when a guitar plays a single note or chord.