said by TheMG:Not sure what I was thinking on the frequency. I'd just finished getting zapped by a phone ringer circuit that I think is 20 Hz so maybe that confused me as it did hurt a little bit!
Actually, half-wave rectified LEDs will "flicker" at 60Hz.
Full-wave rectified LEDs will also "flicker", but at 120Hz, which makes it much less noticeable.
Toss in a capacitor and now you've eliminated the flickering entirely.
Unfortunately, it seems that manufacturers of LED light strings don't find the cost-benefit ratio worth it, even though we're talking about pennies worth of extra parts.