Push button 4027

Discussion in 'General Electronics Chat' started by newbielectronics, Aug 29, 2006.

  1. newbielectronics

    Thread Starter New Member

    Aug 29, 2006
    I am new to electronics and I was wondering if you could tell me how to use a 4027 JK flip flop to create a simple on off toggle switch with a push button. I was also wondering how you know which pins to wire and what each pins function is. I know there is a datasheet but I still don't know what Q and related mean how to use them and what value of capacitors and resistors I need around the circuit. How do you figure all this out?
  2. pebe

    AAC Fanatic!

    Oct 11, 2004
    This link may help you understand the JK flip flop.

  3. lightingman

    Senior Member

    Apr 19, 2007
    Does it have to be a 4027 ?

    It is very easy to do it with a 4013.

    Input to clock (with pull down resistor of about 10K), tie data input to inverted Q output, tie reset and set to logic "0".

    Now if you are using a switch, you should be aware of switch bounce problems I.E. the noise caused by the switch contacts when they come together or move apart.

    There are a few ways of overcoming this, but try this one:-

    Connect one end of the switch to VCC, the other end to a resistor (10K) to GND.
    From the junction of the switch and resistor connect a capacitor with the other end of the capacitor (10nF) through another 10K resistor to ground.
    At the junction of the capacitor and resistor, connect a diode "anode" (1N4148, 1N916), and then the cathode to the clock and pull-down resistor on the 4013.

    If the switch is very bad, it may help if you put a small capacitor accross it (about 470nF)