On 05/15/2018 03:38 AM, gregz wrote:

[snip]

Holiday lights flash 60 times a second, 120 if off a bridge rectifier.

The flashes are the same length. Without the bridge rectifier, every
other flash is dark (LEDs don't emit light when reverse biased).

Most (non-bridge-rectifier) strings I've seen have 2 series (each 25-35
LEDs) using opposite polarity, so there are still 120 flashes per second
(alternating between series).

Some of the flashes I add are about .5 second on. The others are 3 times
that long. You can see a video at http://notstupid.us/video/xmas2017.mp4
or http://notstupid.us/video/xmas2017.webm . Almost all of these lights
are LED. Flashing is done using a small computer (Arduino with
solid-state relays).

--
Mark Lloyd
http://notstupid.us/

"If people are good only because they fear punishment, and hope for
reward, then we are a sorry lot indeed." -- Albert Einstein