snubber

[Morte615]

Aka snubber network, a snubber is a small male edison connector (with 2 prongs) that has a 47K 1W resistor placed between the two prongs. This device is plugged in-line with an LED Christmas Light String to prevent the lights from flickering at low intensities. This also allows the LED lights to turn off completely with no ghosting.

Why is a snubber needed? As quoted from the link below,

This is a capacitive effect of the LED's bleeding off when the AC crosses 0 and the triac turns off. It causes an overshoot. If you add enough LED strands together, you get this huge overshoot that actually powers the LED's for a bit until the next triac turn on. So in effect, the LED's don't turn off because they're kind of powering themselves for a bit. With a single LED strand, those little humps are nearly 10 volts in amplitude. Much more than this and you'll actually light the LED's.

Here is a video of LED strands without a snubber, then with a snubber.
http://vimeo.com/8666024

More information on why snubbers are needed and how to create a cheap one with no soldering needed can be found here on the Planet Christmas Forums .

See also Snubber Network.