Glitches on cd 4013

Thread Starter

hcasal1963

Joined May 14, 2014
5
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
 

#12

Joined Nov 30, 2010
18,224
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.
 

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ronv

Joined Nov 12, 2008
3,770
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.
 

#12

Joined Nov 30, 2010
18,224
Sorry. Couldn't read the datasheet properly. All those pins marked "clock 1" "reset 1" and I got confused.
 

ErnieM

Joined Apr 24, 2011
8,377
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.
 
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