It is my understanding that LCD’s operate on DC yet my string plugs into AC without any adaptor. How does this work? Is there a tiny adaptor and the stem of each bulb?
L E D not LCD.
Light emitting diode, not liquid crystal display.
And to answer the question, LEDs are diodes, and they turn AC into DC. Current can flow through them one way, but not the other. The LEDs are on for one half-cycle, then off for the other half. Each LED needs about 2-3 V across it in order to turn on; this is called the voltage drop. For 120 V, you can put 60 (assuming a voltage drop of 2 V) together in series and you won’t need a dropping resistor; for fewer LEDs you’ll need an appropriate resistor, but these are small enough they can be molded into the plug. Most cheap strings are generally wired up like this.
I don’t know the answer, but it would be cool if the answer involved arranging the LED’s into a bridge rectifier with correct voltages achieved purely through adding up voltage drops.
Based on the ones we have I can say that Q.E.D. is correct. They flicker just enough be annoying (to me anyway) which I assume is because they are flicking on and off. (They look fine if I look straight at them but if I move my eyes or move the strand the flicker becomes obvious.)
We tried some outside and I can stand them a short while straight on, but they make me sick after a while with the flicker I see. Seeing it peripheraly is worse. I hope that when governments keep installing these as energy saving lights, they consider that people are bothered by the flicker, and put in a capacitor to provide a steady light. Even 5% of the public being affect, is a large number. The percentage used is random, I have no stats on it.
I wasn’t even drunk when I wrote that. :smack:
Very well, thank you.
I bought a string last year. I intended to hook them up to a solar panel, but I was able to find a set already built with a solar panel. Yay! No outside plugs (weve got very few and very inconvenient outdoor plugs). Big problem – between our northern latitude and the positioning of our house and surrounding woods, we really don’t get enough light near the solstice to charge up the lights at Christmas time. But the lights look really nice outdoors in the summer.
This year we got two strings of LED lights that plug in. They work fine, consume less electricity, and last longer. And the blues are much brighter than incandescent bulbs.
The technical details are as given. Yeah, you can see flicker if you’re close and move your headf. I find that I don’t have a problem with ones far away, on a fixed tree or something.
Something’s fishy here. The voltage drop in volts on an LED is about what the photon energy is in electron volts, so more like 2 for red ones and more like 5 for violet ones. But the solid color strands from Philips don’t seem to be made much differently. If there’s a dropping resistor in the plug, it’s going to dissipate a few watts and feel hot.
Could there really be separate dropping resistors in all the bases?
Put the end of a pocket comb between your teeth, clench tightly, and sproing the end like a Jew’s Harp while looking at your LED lights.