The filament bulbs are almost all like this. Not too bad if they're using an H-bridge (120Hz with high-ish duty cycle), but Christmas LEDs I think might use no

The filament bulbs are almost all like this. Not too bad if they're using an H-bridge (120Hz with high-ish duty cycle), but Christmas LEDs I think might use no separate diodes at all, just relying on their own diode-ness. That means they're 60Hz with a less-than-50% duty cycle. Filament LED bulbs (the ones that look almost exactly like clear incandescent bulbs with a visible filament when turned on) do this because they have to fit their electronics in the tiny metal base. Room enough for some diodes (and maybe a capacitor), but usually not a full set of high frequency switching electronics like in most other LED bulbs (although I've seen some filament bulb tear downs that might show more advanced electronics). But again, doesn't bother me due to their high duty cycle and relatively okay refresh rate. (At least, this is all my impression. Please correct me.)