Hi,

Just a quick question, If I connnect pin 14 CLK of counter 4017 to Vcc 9Vdc, are the ouputs of 4017 that connect with LEDs turn on at the same time?

Thanks

 

The 9V will act like the clock everytime you touch it to pin 14. So if you power your circuit then touch 9V to pin 14, one of the outputs will come on and stay on. If you remove the 9V from pin 14, the same output will stay on. If you touch 9V to pin 14 again, the next output will come on and so on. This does not take into account bounce that might be produced as you touch the 9V to pin 14.

Also, if you decide to do this, put a 10kΩ pull-down resistor on pin 14, otherwise it will be floating and you may see strange things.

Take a look at the timing diagram in the datasheet for a better visual.

 

To turn all the LED's on a once you need to have the LED's connected thru a resistor to Vdd. Connecting pin 15 (rst) high will cause all the outputs to go low and all the LED's will be on.