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4017 clock enable not working? Answered

Hi. I have a 4017 chip taking clock inputs from a de-bounce switch circuit. I have been trying to get the first two outputs on, one after another, with the second of these o-p's putting pin 13 (clock enable) high which I thought freezes the chip in effect. However this doesn't seem to be happening with my circuit. I know everything is in the right place. Reset is held low, I have one led on pin 2 and one on pin 4, both with appropriate resistors. I had the clock enable on o-p 4 and that worked. I repeatedly pressed the button and the led's didn't come on. But with clock enable on o-p 3, I presses the button and the first led came on after about 9 presses. 
If someone could give me some pointers it would be greatly appreciated. 
Many thanks 


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Best Answer 8 years ago


Make sure you have a pull-down on the enable pin of 10k or more (tying enable to gnd) and your other connection from op3 to the pin. If enable/reset are just floating or connected to a non-currently-active output pin strange things can happen - it's important to keep them directly pulled up or down to whatever you need.

LED Maestro
LED Maestro

Answer 8 years ago

Oh yeah. I always seem to forget the pull down res. thanks for that. It's working now I have that resistor on enable.
Many thanks again