Rewiring christmas lights from series to parallel?

Question

I am doing a project where i need about 100 of the small christmas lights. I need to be able to light them on command. I also need them to plug into a 120 v wall outlet. My problem is, when i light just one or two of the lights, they blow. How can i reduce the voltage going to them so that they will not blow, yet raise the voltage when i need to light a larger number of the lights? Thank you for your help.

Answer 1

tray looking for light's that have less voltage. or ask you'r retal store .

Answer 2

As you suspect, the light bulbs are designed for less than 120v, and will blow if you go that high. To estimate the voltage rating for the bulbs, count the bulbs in the string and divide 120V by the number of bulbs.

You might get lucky and hit a "standard" voltage, such as 5 V, and be able to use a computer power supply (which has 5V and 12V outputs.)

You are incorrect that you have to raise the voltage to light more of the bulbs. If truly wired in parallel, all bulbs see the full voltage all the time. Instead, you may run into current (amps) trouble. Each bulb will use about the same current, so as you turn on more of them, the current, not the voltage, goes up.

Hope this helps.

Answer 3

You could use a variac (variable transformer). This would control the supply voltage to your lights and therefore control the amount of current that the lights draw. The reason the lights blow up is because they are only rated for a small wattage and when you put 120V across them, you're putting many time more power in than they can handle.

This model here will run you about $250:
http://variac.com/staco_variable_transformer_3pn221.htm


P.S. If you don't know what you're doing around electricity, you really shouldn't be playing with it. Be careful!

Answer 4

Get a transformer with an output voltage equal to the rated voltage of each lamp. I think there are about 6 volt lamps. You can put the 6V lamps in parallel up to the wattage rating of the transformer. However if you put those 6V lamps across the 120V line voltage they will obviously burn out from overvoltage.

Since they are in parallel and all see the same voltage you can add or subtract without having to change the voltage.

Answer 5

you can use an inverter to plug the lights in with. You know the things that have the big black boxes as the plugs? They convert AC to DC, and can do so at whatever perscribed voltage is listed on the plug.