Power supply for 300 LED from AC
I want to derive power supply for 330 LED's ( 6 rows of 55 LED's in series - Each LED 3.8v DC ). How to derive the circuit ? Any Idea ? Without transformers.
if for lighting you are better off using a lighting class LED than inefficient 5mm parts. What is it you want to accomplish?
to eliminate 40w flouracent tube
i want to use it for home lighting instead of 40W flouracent lamp. what do u mean by lighting class LED ? Where we can get it ? I have only 5mm LED with 3.9V DC rating.
40W flourescent or 40W incandescent replacement (which is actually only around a 10W fourescent)? The incandescent is only going to put out 400-500Lm but much of it is lost to the reflector and the rest of the room instead of going toward your work surface.
Your 330 LEDs will put out 300Lm, if you are lucky, using 25W to do so. 3 DealExtreme: $5.50 Rebel LED Emitter on Star (0080 BIN) driven by DealExtreme: $3.32 GU10 3*1W 300~320mA Constant Current Regulated LED Driver (85~265V AC) will put out 240Lm for 3W
40W flouracent tubelight
its 40W flouracent tubelight. i want circuit diagram to derive the power supply for 330 LED's from 220V ac direct without transformer. Any idea ?
the 40W tube will put out 2500Lm of which about half is actually reaching your work surface. You might get away with 600Lm from LEDs for a comparable amount of light on your work surface, but that is 600-1200 or more of your little LEDs or 6 of the ones I reccommended. Two of the drivers I recommended is still less expensive than building one yourself.
But i want to doit myself
i want to do it myself the power supply. i want to know the circuit diagram for that. please help
12 DealExtreme: $5.50 Rebel LED Emitter on Star (0080 BIN) LEDs and an HV9910 circuit to drive them
What is the color of the LED? White? Why 55 in series? To avoid transformer?Originally Posted by janeceline
Hi there Jane,
We were talking about an LED circuit the other day that runs off of
220vac mains. It's here on this forum somewhere. It uses a capacitor
and a bridge rectifier to run a string of LEDs. It does not require
a transformer. To run that many LEDs you would use a few separate
strings all driven the same way. Sound interesting?
Won't it work if 230VAC is directly given through a series resistor with out rectifier and capacitor?
no... it will blow all the LEDs
Why? In one half of the AC the LEDs will glow and in the other half 55 LEDs will remain reverse biased. 55 LEDs in series must be able to withstand this reverse voltage. Is it not?
Well I did not see about the reversed ones, but that is beside the point. Unless there is a bleeder resistor across each and every LED differing leakage currents will cause them to blow since they will not share the voltage equally.
another way around that is to have a single string with anti parallel LEDs all the way up instead of anti parallel strings... or is that what you meant?
Last edited by Ubergeek63; 26th November 2008 at 04:56 PM.
Be safe. Do it with an isolation transformer if it is powered by mains. Better yet, buy a compliant DC power supply to power your low voltage circuit.
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