What's a snubber?

[martymiller]

I keep seeing people talking about adding snubbers to their strings of lights, etc. to correct certain problems. One problem, I have no idea what a snubber is, what it does and why you'd use it. Any help?

[evan.a]

here's a pic

[bisquit476]

They have them at Lowes under Holiday Living item #268487 on sale for $0.99 ea.

[-klb-]

For the purposes at hand, the above answers are correct, but it is an improper use of the term.

Actually, in triac applications, a snubber is a LC filter to prevent high dV/dt impulses from switching the triac back on when shutting off inductive loads. Generally LOR loads are not inductive, and LOR uses snubberless triacs, or rather, ones that generally do not switch back on under reasonable dV/dt impulses.

What is actually getting talked about here is just a resistive load that can have a couple of uses. First, it provides a linear load that prevents some issues cased by extremely light loads, and non linear loads. Light loads, and light tails of loads (non linear loading where current is more pronounced during the voltage peak than normal) can allow the triac to switch off early. Adding a few watts of resistive load prevents the triac from turning off early. Though, as I understand it one of the prior firmware updates causes the triac trigger to remain active until late in the tail, as an attempt to fix this issue. Second, all wiring contains a small capacitance. With really long cable runs, and really high counts of LED strings, it is possible that the parasitic capacitance builds up enough to cause a phase shift between voltage and current that causes problems. Adding a small resistive load will dominate the capacitive component, and bring voltage and current back closer to the correct phase alignment, and allow for correct operation...

[greenie95125]

-klb- wrote:

For the purposes at hand, the above answers are correct, but it is an improper use of the term.

Actually, in triac applications, a snubber is a LC filter to prevent high dV/dt impulses from switching the triac back on when shutting off inductive loads. Generally LOR loads are not inductive, and LOR uses snubberless triacs, or rather, ones that generally do not switch back on under reasonable dV/dt impulses.

What is actually getting talked about here is just a resistive load that can have a couple of uses. First, it provides a linear load that prevents some issues cased by extremely light loads, and non linear loads. Light loads, and light tails of loads (non linear loading where current is more pronounced during the voltage peak than normal) can allow the triac to switch off early. Adding a few watts of resistive load prevents the triac from turning off early. Though, as I understand it one of the prior firmware updates causes the triac trigger to remain active until late in the tail, as an attempt to fix this issue. Second, all wiring contains a small capacitance. With really long cable runs, and really high counts of LED strings, it is possible that the parasitic capacitance builds up enough to cause a phase shift between voltage and current that causes problems. Adding a small resistive load will dominate the capacitive component, and bring voltage and current back closer to the correct phase alignment, and allow for correct operation...

Can someone translate that to english please?

--Mike

[Fred]

greenie95125 wrote:

Can someone translate that to english please?

--Mike

Hee hee!

-klb- provided an excellent explaination! He's exactly right.

Reader's Digest version: The resistors or C9's people are using are technically not "snubbers". They're just resistive loads. They can help smooth fades and make LED strings turn off when they're supposed to.

I hope -klb- doesn't object to my translation.

[Paul B. Anderson]

snubber.....it's just a fun word to say.....snubber.....ha ha!

[doug petschke]

Hmmm I trust 1 way of solving this problem is ... add a bunch more lights? or

perhaps instead of a light bulb for a load how about a resister say 10k?

so basically the bulb acts as a drain. consuming the residual voltage caused by the capacitance?

[greenie95125]

doug petschke wrote:

Hmmm I trust 1 way of solving this problem is ... add a bunch more lights? or

perhaps instead of a light bulb for a load how about a resister say 10k?

so basically the bulb acts as a drain. consuming the residual voltage caused by the capacitance?

Next year I plan to use far more LEDs so maybe I'll have to get into this snubber stuff. This year is mainly standard mini-bulbs.

--Mike

[toddmoon]

I am using mini bulbs and LEDs. The shimmer and twinkle effect are just so much more pronounced that I am going strickly LED next year. The light effect are just so much better on LEDs there is no comparison.

[Richard Hamilton]

doug petschke wrote:

Hmmm I trust 1 way of solving this problem is ... add a bunch more lights? or

perhaps instead of a light bulb for a load how about a resister say 10k?

so basically the bulb acts as a drain. consuming the residual voltage caused by the capacitance?

Hmmm, adding more lights won't solve the problem if they are LEDs.
If you use a 10K resistor, it better be a big fat one.... a couple watts.

regarding comment "consuming the residual voltage caused by the capacitance?"

WHAT ?????