Redstone clock leaks current

Question

I built a small clock like the example at the beginning of this video. However, the pulse redstone is triggered each time the cobblestone blocks move over it, instead of just when the glass block goes over it. This is causing a pulse on every cycle of the pistons, rather than on every cycle of the glass block.

What changes do I need to make to the design in order to make this clock work? Should I consider a different design?

Answer 1

Version 1.5 included a whole load of new redstone mechanics, and as such the underlying redstone system changed a fair bit - breaking some devices.

What you have posted is an example. There are plenty of other clocks you can make that work in newer versions, try one of those.