I'd like to add a little to what Leon said (at the risk of getting my head bitten off)...
Re: cutting up light strings (separating snow flakes & the like) - the key to this is how the strings are wired and the rating of the bulbs. As Leon points out, the lights on the snow flakes are probably wired in series, meaning that the power goes through each light, one after another. When wired this way, each bulb only receives 2.5 or 3 (or whatever - depending on the number of bulbs wired in series) volts. Multiplying the number of bulbs in a series by their voltage rating will generally result in the total rated voltage (about 120v in the US). And these days, the mini-lights generally have a fail-safe mechanism, where when the filament (light) burns out, a bypass shunt closes, shorting-out that bulb. When the bulb is shorted-out because of this shunt, all the other bulbs in the string have to "take" the extra voltage that the failed bulb would have been consuming - over-voltaging them (a little). With each additional bulb failure, the situation gets worse & worse for the remaining bulbs, & they'll eventually have an avalanche of failures. That's why you need to replace the bulbs ASAP after it fails.
Now, some light strings are a little more complicated. They are wired in series / parallel sets, where half (or a third or whatever) of the bulbs are chained one after another in series, and the other half are in their own series, wired in parallel with the first series. In this case, removing one bulb will only cause half the string to go out (since the other half is in its own series). The multi-series strings will have extra wire(s) at points in the string. And strings wired this way don't conform to the general voltage rule (volts-per-bulb x bulbs = supply voltage), but will instead add up to 2x or 3x the supply voltage (since each series substring adds up to the supply voltage).
I haven't seen these, but the strings Leon mentions with a 70 count at 3v or the 20 at 12v are probably both wired as a 2 parallel sets of series-connected lights (since the bulb count x bulb rating comes out to around 2x the supply voltage). And, theoretically - not that I'd recommend anyone do this - if one knew how the string was wired, the two series strings might be separated from each other & controlled individually.
Finally, as Leon mentions, the C9-type bulb (and the like) is a special case. These bulbs are rated at 120v, so are all wired in parallel - that is, each bulb is connected directly across the supply (so the bulbs don't feed one-another).
Hope this helps explain...
--Dave
...what if I was to place a resitive load that matched the other flakes in the circuit before each individual flake?
Thanks again,
Eric
[Note: Just answering the question. I'm *not* suggesting that anyone should cut up their light strings - for any reason. If you choose to do this, make sure you know what you're doing & that you are safe in doing so.]
Hi Eric,
I think that would work. But I don't think it's a good idea...
First, this is a *very* inefficient solution, as you'll be wasting far more power than you're "using" (say there are 4 snow flakes; splitting it into 4 separate circuits & inserting appropriate resistive loads into all 4 circuits will quadruple the total power, wasting 3/4 of it).
2nd, the resistive load will probably get quite hot - so it needs to be protected from small (and large) fingers, can't come into contact with flammable materials, etc. Also be aware that, as components (& wires, etc) get hot, their values can change, insulation breaks down, etc.
If you're absolutely sure you want to go this route, be sure that the resistive load is rated at a high enough power (watts) to be able to dissipate all the power in the circuit (i.e. make sure it can be placed straight across the input power line - say, 120v) and is properly enclosed, insulated, etc. It needs to be able to handle line voltage because in the worst case, in unlikely event ALL the mini-lights burn out, your resistive load will be the only load on the circuit, so must be able to handle the current & power.
In my opinion, a (much) better solution would be to disassemble the snow flakes & replace their lights with (short) strands that don't need to be cut up. Or make wire-frame snowflakes & wind them with complete strings that you can then control individually.
-- Dave