Simple debounced switch design help

Discussion in 'General Electronics Chat' started by EonsNearby, Nov 20, 2010.

  1. EonsNearby

    Thread Starter New Member

    Nov 20, 2010
    I am a sophmore at an university. I am taking digital logic and intro to computer hardware class, and I need help with a lab. I am supposed to find a simple design for a debounced switch that can be built using the materials in our lab (as far as I know, we don't have any resistors). However, I cannot find a simple design for one. All we have to work with are some standard TTL chips (7400, 7402, 7403 just to name a few). It also doesn't help that the teacher hasn't talked about these in the lecture part of the class, so I'm not entirely sure what a debouced switch really is (I did some internet research and have the basic idea though). Can someone help me find a design for a simple debounced switch? I think I found one, but it mentions that I need some resistors (found here:, p. 3 figure 2). Would I really need the resistors and is it really a debounced switch?
  2. EonsNearby

    Thread Starter New Member

    Nov 20, 2010
    I know we have JK Flip Flop chips and D Flip Flop chips, but I don't know about any other Flip Flop chips
  3. SgtWookie


    Jul 17, 2007
  4. Wendy


    Mar 24, 2008
  5. BillO

    Distinguished Member

    Nov 24, 2008
    Hi EonsNearby,

    For the circuit in the lab you posted, and for the other one presented (I guess some people do not read well), yes, you would need resistors.

    In any case, do you have access to a single pole, double throw (SPDT) switch, like the one in the lab schematic?
  6. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    With no capacitors, and the fact you are given a SPDT switch, it appears you are to build the S-R latch on page 3 of the attachment.

    --ETA: Reading the first page:

    ---ETA Again.... Clock a few FF's together from the input signal, and when they all match, output that value.