This article teaches you how to make a redstone pulser that is turned on by flicking a lever on/off. It's perfect for clock dispenser mechanisms. However, beware: If the game lags, it may become off, and many servers don't allow it anyway.
- Place down the lever.
- Put 1 Redstone in front of the lever, with one on each side of that.
- Place 1 Repeater next to one of the side Redstones, facing perpendicular to the Redstone line.
- Place the other Repeater on the other side Redstone, facing the opposite direction but still perpendicular to the Redstone line.
- Place another Redstone line on the side that you want whatever you are activating (Piston, Dispenser, whatever).
- Place whatever you are activating.
To turn it one, just flick the lever on/off once, but quickly.