I have the following circuit set up on breadboard. It is supposed to toggle through each of the three outputs each time the button is pressed. At power up, output C should always come on high. As drawn it works as expected.
BUT! If I eliminate the NOT gate, it does a strange thing. It powers up OK, but the first time the button is pressed it usually goes into a random state (often all outputs high) and locks up. Further presses do nothing.
I don't understand why this should happen. All that has changed is that the clock changes on the button release rather than the push, and the clock edge may be slower and less clean. But why should the 4013 care if the clock transition is a bit slow? Surely all that should happen is that it might skip through a few states due to extra bouncing, but not lock up?
Can anyone explain why the NOT gate makes such a huge difference?
BUT! If I eliminate the NOT gate, it does a strange thing. It powers up OK, but the first time the button is pressed it usually goes into a random state (often all outputs high) and locks up. Further presses do nothing.
I don't understand why this should happen. All that has changed is that the clock changes on the button release rather than the push, and the clock edge may be slower and less clean. But why should the 4013 care if the clock transition is a bit slow? Surely all that should happen is that it might skip through a few states due to extra bouncing, but not lock up?
Can anyone explain why the NOT gate makes such a huge difference?
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