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  1. pier1

    white led

    Hi AG         I removed the led light from the roof top to put a better heat sink and when i touched the track side i got a good shock, The capacitors were still charged . Should i put and resistor across the capacitor bank so that they get discharged as soon as it is put off ? If so which...
  2. pier1

    white led

    Hi AG         Thanks for the circuit. Actually I am not building the circuit for 6 led's but i wanted to know the calculations for deciding the number of led's used for certain voltage available because i read somewhere in the web that u can use leds in series provided the voltage across the led...
  3. pier1

    white led

    Hi AG         Now suppose i have only 21 volts dc at the o/p of the power supply and i have to connect led's in series . Assuming the forward voltage is 3.5volts, can i connect 6 in series so that the total forward voltage reaches 21 volts dc ? I dont know the exactly how to calculate the number...
  4. pier1

    white led

    Hi AG         I made a board of 72 X 24 mm in size and the same size for the heatsink with a thickness of 3mm . Would this be a sufficient heatsink for a continious operation . I want to isolate the transistor from the heat sink and screw it up (Heat sink)on the roof of my room . Thanks Pier .
  5. pier1

    white led

    Hi AG         The circuit was on test for 3 days continiously and working fine . People are asking me how much power it consumes from the mains . Bulbs consume 60Watts as written on it when we purchase it here . Do we have to connect an Ampere meter in series with the live mains i.e.230/250...
  6. pier1

    white led

    Hi AG         Its right as u said . The voltage across the 22ohms resistor is 0.6volts when the mains voltage reaches 345Vdc . The 13005 is getting very hot and i 've put a bigger heatsink now . I will put it under testing and let u know the result after 1 or 2 days . Thanks a lot for ur...
  7. pier1

    white led

    Hi AG         I connected 22 ohms . Now the voltage across is 0.58 . How about reducing the resistance little more ? Thanks Pier.
  8. pier1

    white led

    Hi AG         I am such a fool, I forgot to connect the 3904 in reverse when i corrected the 13003 properly . Now its fine . The voltage across the 27ohms is 0.56 volts. I dont understand AG how are u able to find faults without seeing the circuit I connected . Thanks a lot AG . as i said is...
  9. pier1

    white led

    Hi AG         There is no voltage across 27 ohms resistor when i measured it ? what could be the reason ? Thanks Pier
  10. pier1

    white led

    Hi AG         Ur great!!!!Thanks for pointing out my mistake . The collector and emitter was in reverse . Now it is very bright and i have a little doubt will it blow off !!! Where do u measure its current AG . I am in front of it now . Thanks Pier
  11. pier1

    white led

    Hi AG         I apologise for electrocuting myself :-X . I measured the voltages at different parts of the circuit : across 27 ohms resistor : 0 volts (no voltage) at the base of 13003 with respect to gnd : 14.25 volts across the 10k resistor : 0.59 volts at the collector of 13005 with respect...
  12. pier1

    white led

    Hi AG         The circuit works fine now, but no brightness . Before with high wattage resistor it was really bright . But now it is less . I forgot to tell you AG that I am using 49 white leds . What could be the reason ? Thanks Pier.
  13. pier1

    white led

    Hi Ag       I am still searching , I've asked a shop owner for the same and he said he will let me know in 2 days . By the way AG hows 13003 for the small one ?
  14. pier1

    white led

    Hi AG Thanks a million :D.The circuit works!!!!!!!. The 13005 is warm with a heatsink . I tried till only 280volts dc . I have to look for a high voltage transistor of to92  package (400volts as you said) for testing till the higher end of voltage . Mean while if you find some part numbers...
  15. pier1

    white led

    Thankyou so much AG, I am using MPSA42 as the small high voltage transistor . No problem naa ? Thanks Pier .
  16. pier1

    white led

    Hi AG         Thanks a lot for the circuit . I will build the circuit today itself and test it, but one doubt (must be a dumb one, dont feel bad : i am weak in electronics) as u said before should i connect a high watt resistor as per previous calculations for the led's in series ?!!! Thanks...
  17. pier1

    white led

    Hello AG               I tried , there are only 80 to 100 volts available (darlington) .I found a bu808 on the net but i dont get it here. Can we do it with a 13005 ? . Thanks Pier
  18. pier1

    white led

    Hi AG,         How do i do that ? do you have any circuit for that  ? and till what voltage can we regulate ? . Wont that be tough AG to regulate such high voltage!!!! Thanks Pier .        
  19. pier1

    white led

    Hi AG         I am sorry for asking that question . I looked into the datasheet only after posting my question, But I would still like to know the element Which is used as a reference . I am interested to build it and test it AG if you give me the values . I dont mind if it takes some time even...
  20. pier1

    white led

    Hi AG         The circuit looks complicated but it is of interest to me . I dint understand what is that reference (200mV) you mentioned .
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