Logic Levels of DIP Switches and Push Button

Discussion in 'Homework Help' started by wind_blast942, Oct 9, 2010.

  1. wind_blast942

    Thread Starter New Member

    Sep 7, 2010
    Hi all

    I am currently running a simulation for my project. However i am curious about the actual logic levels for a DIP switch and push buttons that i will be using in the actual circuit.

    According to the simulation software i am using (Circuitmaker) an unpushed push button will give a high impedance value; and since there is no DIP switch model in the program, i assume it to be similar to a logic switch (Logic 0 when open, 1 when close)

    My question is: Is the assumption that a unpushed push button have high impedance and that a DIP switch automatically outputs a logic 0 or 1? If not is there any method to make my assumption true in an actual circuit?

  2. Markd77

    Senior Member

    Sep 7, 2009
    Try adding a resistor to the logic 1 voltage level and the pushbutton to ground. It's called a pullup resistor and is fairly common. Real switches also bounce which can need more consideration.
  3. Georacer


    Nov 25, 2009
    A DIP switch will conduct either Vcc or Ground, as clear as your wiring gives it to the switch.

    A push button will conduct either the logic level it is connected to, or it will be an open circuit. This is quite definite in the low-voltage level that IC's work.

    However, as Markd77 posted, bouncing is a serious drawback of this type of switches. My suggestion is that in order to secure a pure and bounce-free logic level for your input, you should use a NAND latch debouncer. Google it for more info or try the second page of this blog: http://www.ganssle.com/debouncing.htm