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Circuit board for flashlight - need help

Discussion in 'LEDs and Optoelectronics' started by makowka, Jan 17, 2013.

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  1. makowka

    makowka

    4
    0
    Jan 17, 2013
    Hello to all board members

    May name is Simon. I would like to built a head-flashlight witch such bulbs:

    http://www.conrad.pl/Żarówka-wskaźn...mm,-przejrzysta.htm?websale7=conrad&pi=720183

    Supply 3,5V, 200mA. I would like power it through 3 AAA batteries (3x1,2V), connected in parallel. The batteries would be rechargable ones, so I think, there is a need for additional components to stabilize the power supply. I want to apply two red and two green lights, so there must be a possibility to switch between the two groups of lights, turning the whole thing off and on. I have no idea of electronics, but know some fundamental laws. Could someone please help me to design a circuit for such a flashlight?
     
  2. BobK

    BobK

    7,682
    1,688
    Jan 5, 2010
    3 x 1.2V = 3.6V which is close enough to 3.5V, so I think the batteries can drive this bulb directly.

    Bob
     
  3. makowka

    makowka

    4
    0
    Jan 17, 2013
    Yes, but there are 4 bulbs, two green and two red. I would like to switch between the two red and two green lights. Maybe there has to be a resistor, to reduce the voltage? How should I connect the batteries and the lights? Parallel or in series?
     
  4. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,497
    2,838
    Jan 21, 2010
    OK, you would need the batteries in series to power the bulbs, and the lamps sound like they need to be in parallel.
     
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