Droppers and dispensers only react to rapid one-tick pulses if the signal strength is below a certain threshold (or the redstone wire length is above one, depending on how you word it).
This video I recorded shows the issue more clearly, in addition to the screenshot.
http://www.youtube.com/watch?v=RxOUAR8Q5V8
Related issues
is duplicated by
MC-9349
Repeaters not turning off in a comparator-clock
MC-11348
The droppers reacts differently in singleplayer and multiplayer mode.
MC-11494
Comparator only graphical redstone flickering.
MC-11512
redstone loop only powers dispenser once from the back
MC-12109
the /testfor command in command blocks doesn't support the team,score_name or score_name_min argument
MC-12203
Clock bug
MC-13213
Rapid pulse generator glitch with redstone length/strength.
MC-14230
Depending on distance from comparator, dispensers give out one or two pulses
MC-25797
Command block not updating
MC-35046
Dispensers/Droppers only activate when Comparator is at least 3 Blocks away
MC-44536
Redstone clock not triggering all attached devices
MC-45431
Redstone Comparator clock bug (Renamed)
MC-45666
Powering one face of a command block with a clock provides constant power, until switching.
MC-49543
Misbehaving Comparators
MC-50761
Redstone clock does not activate commandblocks
MC-50893
Comparators connected to Command Blocks don't shut off after executing a command
MC-50906
Command Blocks doesn't get updated with a comparator clock
MC-51823
Command block with comparator clock
MC-55635
Comparator clock not activating command blocks
MC-56133
Clock too fast for Command Block
MC-56265
Comparator clock not working with command blocks
MC-56298
Command blocks not executing while triggered by a very fast clock
MC-58586
comparator redstone clocks doesnt working
MC-66739
Command Blocks can't keep up with comparator clock?
MC-71010
One specific comparator timer doesn't power command block
MC-75270
/execute command not working in command blocks
Attachments
Comments
migrated
rydian
Here's a quick overview screenshot.
migrated
Confirmed and applies to all powered mechanisms like pistons, repeaters, noteblocks...
migrated
Also confirmed. With a stronger signal, it shoots once and then stops.
migrated
Yes, I reproduced it and it is indeed a bug.
migrated
Now that I think of it, that works as intended, let's see how this comparator clock works: 1. Comparator is in subtraction mode.
2. You provide a signal from the back, comparator outputs strenght of 15 in the front. This loops to the side where the signal is 13. Comparator is in the subtraction mode: signal A - signal B. In this case signal A is still 15 but B is 13. So now the output of the Comparator is 2. That's why powered mechanisms won't react because the signal does not shut off completely but goes down to 2.
rydian
Looks like you're right. My initial tests using comparators as fast clocks (attached screenshot "othertests") had the pistons placed slightly differently.
migrated
Thanks, as you explain it it's very easy to understand 😛