journeyman0217
Senior Member
- Location
- Tennessee
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- Electrician
do all LED's operate on dc voltage?
LED voltage
- Thread starter journeyman0217
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mopowr steve
Senior Member
- Location
- NW Ohio
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- Electrical contractor
Not nessasarily?
Im thinking about Christmas light strings of LED that naturally conduct on the 1/2cycle of AC. (As a diode does) and other various products. Which tends to look like strobe-flicker especially if you rotate your field of view (your head) when looking at them. I notice this also with LED tail lights on cars going by. I hate that.
I don't know for sure but would believe that led products with drivers probably have a pulsated DC?
Im thinking about Christmas light strings of LED that naturally conduct on the 1/2cycle of AC. (As a diode does) and other various products. Which tends to look like strobe-flicker especially if you rotate your field of view (your head) when looking at them. I notice this also with LED tail lights on cars going by. I hate that.
I don't know for sure but would believe that led products with drivers probably have a pulsated DC?
Electric-Light
Senior Member
They do indeed. Each LED chip runs at a little over 3 volts for deep blue LEDs used for lighting LEDs which are almost exclusively made with pcLED, an LED lit fluorescent lamp element. Each element can be the size of a tick to egg yolk sized and holds anywhere from one to dozens of blue LED chips buried under a thin layer of phosphor mixture in silicone rubber.
This element for example is made from 8 blue chips connected in series under one phosphor package. Ten packages are connected in series again to form a module that is driven off of a ballast that provides about 0.04A at 240v DC. (mfg by Cree in 33rd week of 2013)
Amen. i hate that also. Some flashlights do this too. Tail light LEDs are usually ballasted with a resistor and it's given straight power while braking and pulsated to dim when you're not on the brakes. LEDs have no afterglow so the pulsation doesn't get filtered out. Pulsating them too fast causes excessive radio interference. Current modulation is more expensive and it tends to cause a color shift.
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