How do I make a 4 volt 2 watt battery pack?

Discussion in 'The Projects Forum' started by Coastersplus, Aug 5, 2012.

  1. Coastersplus

    Thread Starter New Member

    May 31, 2012
    1
    0
    I am making a robot with 4 transistors and 3 resistors. But for the circuit to work, I need 4 volts and 2 watts. How would I connect batteries to get that?
     
  2. cork_ie

    Member

    Oct 8, 2011
    348
    58
    6V battery with a LM317 regulator adjusted to 4.0V is about the easiest way I can think of. It is quite possible your circuit will work directly off 3AA cells in series (4.5V)
     
  3. #12

    Expert

    Nov 30, 2010
    16,250
    6,746
    Most things that say 4 volts don't mean 4.00 volts or I'll blow up. Then there are a lot of people that have an LED labeled 4 volts maximum and they blow it up because they won't tell us what they are doing and they don't know that LEDs care about current, not voltage.
     
  4. bountyhunter

    Well-Known Member

    Sep 7, 2009
    2,498
    507
    Three NI-CAD or NI-MH will be 4.2V - 3.7V over their full life.
     
  5. crutschow

    Expert

    Mar 14, 2008
    12,981
    3,221
    How long do you need this 2W to last?
     
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