So I have learned that in order to shorten christmas lights, you need a resistor. And unless you get a very very big resistor (which is expensive and hard to find, or use a heatsink, or string many together to up the wattage a lot), it will get very hot and you can't let it touch anything.
I don't know what I am missing why I needed a resistor for shortening a christmas string unlike the shorter string. For example, someone could manufacture a string with 78 bulbs instead of 100, and I am sure they would not have a hot resistor on there.
But why does a shorter string of lights not need a resistor?
I'm not sure why I am needing to add a hot resistor, I wondered what they do in the manufacturing process to determine how to make the string without a resistor? Is it the type of bulb? Or is there something else involved?
Is there a way to emulate the shorter string of lights without the resistor?
Note: these are strings which plug into a wall outlet of 120V. The voltage therefore cannot be adjusted since the power outlet cannot be adjusted.
Answer
The strings are designed to use bulbs whose voltages sum to equal the supply voltage. So a string that uses 20 bulbs for a 120V power source will use bulbs designed to operate at 6 volts. And a string that uses 50 bulbs for a 120V source will use bulbs designed to operate at 2.4V. When you are making hundreds of thousands (or millions) of strings you can have custom bulbs made for whatever voltage you wish.
If you want to remove some of the bulbs and shorten the string, then you must compensate for the power the bulbs were using or run the risk of premature failure of the remaining bulbs which you are operating over-voltage.
A 2.4V bulb designed for a 50-bulb string is NOT "interchangeable" with a 6V bulb designed for a 20-bulb string. No matter how similar they may appear to the naked eye.
No comments:
Post a Comment