How do redstone torches (circuits) work in Minecraft?

Question

I tried reading the minecraftwiki page on the subject, but without an understanding of precisely how the torches work, none of it makes sense. I have a lot of questions, so even an article explaining only a few of the answers would be helpful.

• How is it possible for the torches to work as both input and output to a circuit?
• What if two torches are both acting as output to the same redstone-wire?
• What if one torch is outputting positive/on/true to a redstone-wire but another is outputting negative/off/false to the same wire?
• Is there a practical difference between torches on the ground and torches on the wall?
• When people talk about 'the redstone-torch's block' (ex. wires only carry power 15 blocks from the source block), do they mean the block the torch is attached to, or the block of space the torch is occupying?
• How do I read the diagrams on the minecraftwiki page?

Thanks for any help understanding all of this!

Answer 1

Bob's Minecraft Tutorial, linked by Billy ONeal, is a useful resource, but I'll try to put the basics into words.

How is it possible for the torches to work as both input and output to a circuit?

Is there a practical difference between torches on the ground and torches on the wall?

Depending on where the torch is placed, neighboring blocks will be inputs or outputs, but each neighboring block is EITHER an input or an output - no blocks are both.

• A torch on the ground (in other words, on top of a block) outputs power in the 4 cardinal directions, and also outputs power to any block in the air above it.
• That torch will only accept input from the level below it, so input wires must run straight into the block the torch is sitting on.

To summarize, torches on the ground output to their level and input from the level below.

• A torch on a wall (in other words, on the side of a block) outputs power in only 3 directions (it doesn't output back into the block it's mounted on).
• That torch will accept input from the top of the block it's mounted to, and from the other 3 sides of the block it's mounted to.

In summary, torches on a wall output onto the ground and take input through the wall block.

What if two torches are both acting as output to the same redstone-wire? What if one torch is outputting positive/on/true to a redstone-wire but another is outputting negative/off/false to the same wire?

This has been answered elsewhere, but: If any power source hooked up to that wire is on, the wire will be lit up.

How do I read the diagrams on the minecraftwiki page?

Again, I'll try to break down the basics:

• White squares are just air, nothing special
• Yellow squares are blocks
• Dark yellow squares are blocks a level below (that is, they're an abbreviation for "white on this level, yellow below")
• Grey squares are blocks on the current level with other items a level below

White and yellow squares can then have these items on them:

• Red lines are wires
• Red circles are redstone torches (which may be attached to the side of a block or sitting on one)
• Grey circles are levers
• Small dark grey rectangles are pushbuttons
• Large grey inset squares are pressure plates

So, for example:

• a red line on a yellow background is a wire on a block
• a grey circle on a yellow background is a lever on a block
• a red line on a grey background is a block over a wire
• a grey circle on a grey background is a block over a lever

Within the MCRedstoneSim program you can change levels and see the wiring and such on each level of the circuit, but these extended types of blocks exist so that the whole circuit can be communicated with one set of symbols and no need to show diagrams per level.

Answer 2

How is it possible for the torches to work as both input and output to a circuit?

Watch this

What if two torches are both acting as output to the same redstone-wire?

The wire will be on if either torch is on. Note that actually achieveing this requires a T-junction because redstone wire needs to point in the direction of any sources or sinks.

What if one torch is outputting positive/on/true to a redstone-wire but another is outputting negative/off/false to the same wire?

Isn't that the same question? :P

Is there a practical difference between torches on the ground and torches on the wall?

See the video.

the redstone-torch's block' (ex. wires only carry power 15 blocks from the source block), do they mean the block the torch is attached to, or the block of space the torch is occupying?

Neither. They mean number of blocks of redstone wire. I.e. the initial redstone powered by the torch is the first one off your 15 counter.

How do I read the diagrams on the minecraftwiki page?

No idea. Sorry :(

Answer 3

Simple Boolean logic answer, the input is whatever the redstone torch is on, can be hard-powered or soft-powered, and the torch will NOT the input and hard power the block above them and soft power all blocks around them excluding the block the torch is placed on

As for your questions, in order of appearance.

First, just like a repeater can be the input and output, just looping around

Second, as with any input, they will be ORed together

Third, again, the torches will OR together, and based on the truth table for the OR gate, the circuit will output a 1

Fourth, the main advantage of redstone torches on a wall is that they can power the block below them

Fifth, the block that the torch is on is its input, the torch itself will output, e.g. you have a torch on a block(block: (0,0,0), torch: (0,0,1)), the output is going to be at the torch at (0,0,1) and it is able to reach (0,0,16) if you place a redstone line connecting those 2 points

Sixth, I'm still not sure myself but you can read the top question for that