I'm having trouble with a 4017 IC. I have it wired up as follows:

Relay to debouncer (http://www.elexp.com/t_bounc.htm - Figure 2)
-R = 1M ohm
-C = 0.1 uF
-Relay completing the circuit to ground for the switch
-Using a 4011 IC with inputs tied together to make a NOR gate
-I calculated this to give a 0.1 second debounce time

NOR gate to Clock on 4017
Output to LED's having common cathode (vertical stripe on breadboard)
common cathode strip to resistor (470 ohm)
470 ohm Resistor to ground
Everything is powered from a single 12V 5AH Lead Acid battery

The issue I'm having is that it transitions as 2 pulses when i trigger the relay. If I trigger the relay within a very short time frame after it is released it will pulse as 1 cycle, advancing by 1 led. If I wait more than roughly 1-2 seconds it will advance by 2. Any ideas on the issue?

Thanks,
danuke

 

hi danuke,

A better choice of for the ic would be a 4093 quad dual input NAND schmitt. They are pin compatable with 4011.

The RC filter has a slow risetime, so the output of the 4011 will oscillate as the risetime voltage passes
thru the 4011 input transition/switching value.

The 4093 has a schmitt input which will prevent this oscillation.

Post a diagram of the circuit.

Check the maximum output current from a 4017's output pin?

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Eric
"Good enough is Perfect"

PIC tutorials:
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Bill's: www.blueroomelectronics.com/

 

I take it you're not using the other gates for anything.

You can build a schmitt inverter with three NANDs.

Attached Images

Schmitt 4011.GIF (2.0 KB, 11 views)

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