Glitches on cd 4013

Discussion in 'General Electronics Chat' started by hcasal1963, May 14, 2014.

  1. hcasal1963

    Thread Starter New Member

    May 14, 2014
    5
    0
    I am trying use one CD4013B as a toggle switch .

    PIN 2 tied to pin5
    Pin3 clock to pulse varying from 0 to 12 v
    PIN 4,6,7 to GND
    Pin 14 To 12 V

    When I power on the circuit a glitch, generate at pin 1 , 12 V , How can I do for eliminate this effect ? Pin 1 only must be to begining at 0 V not 12 V.

    Thank you
     
  2. #12

    Expert

    Nov 30, 2010
    16,330
    6,818
    Connect pin one to ground and it can not glitch high.
    Of course, seeing the rest of your circuit would help,
    and please learn to post your datasheet to save us time.
     
  3. ronv

    AAC Fanatic!

    Nov 12, 2008
    3,292
    1,255
    You could try removing pin 4 from ground, then add a cap (.1ufd.) from pin 4 to +12 and a large resistor, say 50k, from 4 to ground. Add a diode across the resistor with the cathode to pin 4.
     
  4. AnalogKid

    Distinguished Member

    Aug 1, 2013
    4,544
    1,251
    Pin 1 can't be grounded because it is the toggled output. Also, it is an output.

    ak
     
  5. #12

    Expert

    Nov 30, 2010
    16,330
    6,818
    Sorry. Couldn't read the datasheet properly. All those pins marked "clock 1" "reset 1" and I got confused.
     
  6. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    7,394
    1,606
    ronv has the answer. It works because the state of the flip flop when power is applied is undefined, and in your case it happens to be incorrect for your needs.

    Consider that a bonus: if it was the other way you would have a defect just waiting to appear someday.

    ronv's RC adds what is known as a power on reset signal to force Q1 to be reset.

    You may consider adding a seccond RC (or connection) like that to pin 10 if you also use Q2.
     
    hcasal1963 likes this.
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