[shanemhansen]

I've wondered about PWM flicker when I started trying to figure out why so many modern car headlights seem like they are strobing to me.

Initially I thought it might be related to the alternator.

I still don't know why I perceive these headlights as having an annoying flicker or why. I'd love it if some (informed) commenter could clear it up for me. Am I imagining it?

[jeroenhd]

Car headlights seem to really cheapen out on the PWN flicker. Even the 2 euro LEDs I buy at the discount store seem less flickery than the lights of some luxury cars. I thought it could be that people are buying the cheapest replacement bulbs they can get their hands on, but then I saw the same thing happening on a new BMW.

I also believe some people are just more affected by flicker than others. Some get headaches or migraines from working under PWM light, others don't even notice.

I'm not a mechanic, but I believe these car lights are capable of achieving some pretty high brightness (necessary for fog lights etc.) but are dimmed under normal conditions, leading to PWM effects you also see in cheap dimmable bulbs. It's especially noticeable for me on those "fancy" lights that try to evade blinding other cars (and end up blinding bikes and pedestrians) and those animating blinker/brake light setups.