looking to make 3904 or 3906 transistor circuit manual transfer load from one to othr

Discussion in 'General Electronics Chat' started by thedarkotaku, Apr 5, 2011.

  1. thedarkotaku

    Thread Starter New Member

    Feb 28, 2011
    hey all, im new to the forums here but i've been dabbling with electronics for as long as i can remember. anyways everyone seems really helpful on here so here goes:

    i have a ton of 3904 and 3906 transistors floating around and i saw this video on youtube:


    towards the end it shows him pressing a momentary button with a few transistors and some leds, manually making one turn off when the other turns off (perhaps a manual flip flop?). i was wondering if anyone could tell me as to where to start on this, as i've been trying to replicate it for days now. all i want to be able to do is hold in a simple tactile momentary button in and have it switch the load from one led to the other. if anyone could help i would greatly appriciate it.:)
  2. Kermit2

    AAC Fanatic!

    Feb 5, 2010
    Would you mind posting what you have done so far in your efforts to recreate the circuit?
  3. thedarkotaku

    Thread Starter New Member

    Feb 28, 2011
    ive tried to modify the circuit here to start with
    (schematic at the bottam)


    i know its nothing like the same thing but i thought since it switched loads from one transistor to the other it would work if i eliminated the capacitors and did some trial and error trying to get it to manually switch loads with no success.
  4. Papabravo


    Feb 24, 2006
    The circuit is called a multivibrator and it comes in three flavors

    1. Astable multivibrator has no stable state and toggles back and forth between two states
    2. Monstable multivibrator (aka One-shot) has one stable state. When triggered it will stay in the one state for a while and return to the stable state.
    3. Bistable multivibrator (aka Flip-Flop) has two stable states. A trigger signal is required to make the device switch to the other state.
  5. Ron H

    AAC Fanatic!

    Apr 14, 2005