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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


    Jan 17, 2013
    Hello to all board members

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


    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.

  3. makowka


    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

    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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