If you're like me, the words 'monostable circuit' mean nothing to you. Until just recently, I had no idea what a monostable circuit did, or why anyone would ever need to use one.
However, I've come to understand exactly what they are, and how very useful they can be! So I've decided to share that information with the rest of the world!
Essentially, a monostable circuit is a device that stabilizes a circuit. That is, it takes an unstable input and produces a stable output. What this means in a practical sense is that if you have a complicated piece of redstone, sometimes when a user mashes the power button repeatedly, it can break. Well, if you've attached a monostable circuit to your device, no matter how many times the power switch is triggered, the device will only activate every set period of time. You can changed that delay, depending on which design you use, but that's the gist of it.
So to summarize, a monostable circuit will prevent your redstone devices from breaking or getting stuck. With me so far? Great! Now let's check out how to build one!
There are a variety of ways to build monostable circuits: a minimum of five, but probably more. I'm only going to cover my favorite one here, but if you're inclined to share a different design, please do so!
Five blocks of any redstone-conducting variety, spaced one block-width apart from each other.
Start from the side of your input, and add repeaters pointing at each block. The first two repeaters should have no extra delay, the third should have one extra delay, the fourth should have no extra, and the fifth should have two extra.
Now add a line of redstone alongside the first block, to alongside the last block.
This step is a little complicated, but let's see what we can do. I had to skip ahead a step in the pictures, so let's examine this picture in two steps.
First of all, you want to add redstone in an L-shape from alongside block 1 onto the top of block 2. Then another from alongside block 3 onto the top of block 4.
You'll notice that those L-shapes quickly became U-shapes (or some other odd kind of shape) because the redstone wire on top of your blocks bonded to the line of redstone on the other side.
What we're going to do now is add two blocks, floating in the air, to block those connections.
Now your input attaches to the first repeater, and your output comes off of the line of redstone on the right side.
Here I've hooked a button up to a piston:
That's all there is to it! Now your unstable, button-based input (in this case) won't trigger your piston over and over again. Rapid button-presses will result in a continuous flow of power rather than a jagged on/off/on/off cycle.
This design will also stabilize rapid pulsars and some clocks, depending on your delay settings.
I hope this helps with your more complicated redstone builds, and don't forget that if you have a better design or use for a monostable circuit, let us know by making your own tutorial!