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convert 220 AC to 3.6 VDC for lighting LED

Discussion in 'General Electronics Chat' started by mamun2a, Feb 24, 2008.

  1. wayne2056

    wayne2056 New Member

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    My Bad

    Thanks DMW... I need to relearn what Xc is and how to apply it.

    Wayne2056:rolleyes:
     
  2. Hero999

    Hero999 Banned

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    Another option is to just use a bipolar LED which will produce no flicker and won't require a reverse parallel diode.
     
  3. Ubergeek63

    Ubergeek63 Well-Known Member

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    better yet just stick the LED in a diode bridge if its a HB, Only junk die come in bipolar LEDs until you get to the expensive stuff that they proceed to charge even more for.
     
  4. dave

    Dave New Member

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  5. mamun2a

    mamun2a New Member

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    thanks all to help me with suggestions.

    i'm fully stupid about the hitek laws. :(
    but i impressed with rodalco's idea.

    dear rodalco, what difference on effecincy LED and general LED?

    mamun2a, dhaka, BD
     
  6. Flarup

    Flarup New Member

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    Many years ago I also used this principle to make a led light up just for signalling, no harm in that.

    But today my interest is on LED lightning, thus there may be a legal harm. As I understood the effect of the capacitor it causes a phase shift (sorry if I use wrong terms, im a bit rusty on this)
    Now the effect of this phase shift is that voltage & current does not follow each other and thus no components are overloaded.

    But that kind of circuits may also cheat the power meter from the electricity company, and thus they are illegal. The same effect is seen on neon tubes where a capacitor is required for the metering to be accurate.

    Also a similar effect is seen from switchmode power supplies in eg computers, where the cheap power meters cannot measure the power consumption of a computer. I don't know why the power meter from the electricity company can handle computers though.

    But besides all that, what is the more power effective, a switchmode power supply or a capacitor? The switchmode can do 80-90% efficiency today. But it is quite expensive. Cheap transformer based power supplies do not go above 50% efficiency.

    Thus using capasitors could be very interesting. Especially now when all the Christmas lightning comes up again.
     
  7. Shehzad

    Shehzad New Member

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    Please Help

    What if i need to have 4 LEDs in series or in parallel ??
     
  8. audioguru

    audioguru Well-Known Member Most Helpful Member

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    With one 2V LED operating from 220V then its current is 21.8mA with a 10k ohm resistor.

    With four 2V LEDs in series operating from 220V and with a 10k ohm resistor the current will be 21.2mA and they will look the same as the one LED.

    LEDs should not be connected in parallel. They are not exactly the same so one will hog a lot of the total current and burn out. Then the remaining LEDs will have more current and they will quickly burn out.
     
  9. Shehzad

    Shehzad New Member

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    you mean to say that, if i connect 4 LEDs in series using the same circuit there would be no change required in circuit ?

    the glow of each LED will be same(as when a single LED was used) or will 1/4
     
  10. audioguru

    audioguru Well-Known Member Most Helpful Member

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    I showed the calculation for the current in one LED to be almost the same as the current in 4 LEDs because the voltage is so high that there is very little difference in the current. Then there is very little difference in the brightness.

    If each LED is 2V and if the supply is only 10V then one LED will have a current of 20.5mA with a resistor of 390 ohms and four 2V LEDs in series and with a 390 ohm resistor will have a current of 5.1mA (one-quarter of the current for one).
     
  11. Insider

    Insider New Member

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    Emergency LED Light with a Battery

    hi,

    I have build a lot of lights of this kind using a 2.2mfd 400VAC capacitor in series with a bridge rectifier, and it has got ample power to trickle charge the Battery which is 6V 7AH, and it can sustain 104 Leds (5mm White LED) for 4 hours.

    some people might think this a hoax, but they dont live in a country which has got 14 hours power outages every 24 hours. So I think I am more desperate than most of you to make the dream come true with a Solar Cell for a Light without mains supply.

    :)
    Insider
    Kinetics Automation
    fahimbaig2@gmail.com
     
  12. audioguru

    audioguru Well-Known Member Most Helpful Member

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    What is wrong with the government of your country? Has it been sleeping for 100 years?
    Everybody else in the world has continuous reliable electricity.
     
  13. Hero999

    Hero999 Banned

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    The government in his country probably censor and monitor the Internet where he lives so him answering that question honestly might result in a prison sentence.
     
    Last edited: Jan 3, 2009
  14. RODALCO

    RODALCO Well-Known Member

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    Which country do you live in to have all these 14 hour power cuts?
     
  15. Flarup

    Flarup New Member

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    Irak??? ;)
     
  16. audioguru

    audioguru Well-Known Member Most Helpful Member

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    India, Nigeria and other 5th world uncivilized countries have poor people stealing the copper wires.
    They also tap into the lines, steal the power and overload everything.

    The governments ignored the experts years ago who said more electricity generating stations are needed for the future. Now they "load shed" to reduce the load.

    The people in charge of operating the electrical grid are sleeping.
     
    Last edited: Jan 3, 2009
  17. Leftyretro

    Leftyretro New Member

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    "this is called reluctance...."

    Actually what you are meant to write is reactance, not reluctance.

    Reluctance has to do with magnetic resistance: Magnetic reluctance - Wikipedia, the free encyclopedia

    Lefty
     
  18. RODALCO

    RODALCO Well-Known Member

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    Thanks for your reply.

    I hope the powercuts will get less and your network improves in the forseeable future
     
  19. blueroomelectronics

    blueroomelectronics Well-Known Member

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    Just thinking aloud, lets say everybody used a UPS wouldn't that just make the problem worse? There would be a massive load increase as people charged their batteries so you'd probably be cut back to 4 hrs of mains power a day.
    The problem needs to be fixed at the source.
     
  20. Hero999

    Hero999 Banned

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    That's because it lots of these countries the government is in charge of the electrical distribution system.
     
    Last edited: Jan 4, 2009
  21. Insider

    Insider New Member

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    Nice Weather and LED Lights

    hi

    Audio Guru and others who showed concern...
    thanks

    the day I posted it was 14 hours
    now as for today it is 15 hours power outage in big cities, with a population +8 million

    and for rural areas its simple No electricity or Max 3 hours supply every 24 hrs.

    So everyone is happy, as we are saving a lot on Electric Bills. :eek:

    and for those who dont know the country name its Pakistan.
    and we do have a lot of civil liberties here including we can say anything to the government for they probably dont give a damn about what we are saying.

    as a week has gone by and we do not have any Petrol available or CNG which is the alternate fuel to drive cars...... so everyone is enjoying the weather at home.

    Insider
     

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