1kHz Square Wave

Discussion in 'The Projects Forum' started by minumula, Dec 29, 2007.

  1. minumula

    Thread Starter New Member

    Dec 11, 2007
    I am working on a circuit and part of the ciruit needs a 1kHz square wave. I had prototyped on a breadboard using the signal from an analog trainer. I want to move the design to a perf board to put the circuit in an enclosure.
    I do not want to use a 555 as I already have one on the cirucit for a variable frequency. I can also build using a astable multivibrator with 2 transistors but it requires 2 cap's and 4 resistors and the values have to be calculated for 1kHz signal.
    Any other way to generate the signal?

    Praveen Minumula
  2. thingmaker3

    Retired Moderator

    May 16, 2005
  3. SgtWookie


    Jul 17, 2007
    Sure, there are lots of ways.

    You COULD use a 556 instead of the 555; that way you'd have two timers in one IC. Lots of advantages in doing so; the 556s can drive up to 200mA output current.

    If you don't need much current from your 1khz clock, you could use a 4093 CMOS Schmitt input quad NAND gate. From one of the gates' outputs, run a 15K resistor to both of the gates' inputs. Then connect a 0.047uF cap from those same gate inputs to ground. That'll give you about a 1kHz clock out for a 5.5VCC. Make sure to tie the remaining unused inputs to either ground or VCC. You'll have three NAND gates left over. If you need more than 1mA current, you'll need to use a driver gate.