I am about to build a circuit with three 74HC595 in series. Looking at ShiftOut tutorial http://arduino.cc/en/Tutorial/ShiftOut, it shows a capacitor connecting the latch pin to ground on the first 74HC595. The second 74HC595 doesn't have a capacitor.
When connected three in series, should I put a 1uf capacitor on only the first 74HC595? Would it hurt to put a 1uf capacitor on all three 74HC595's?
Thanks
Don't put any cap, there is a mistake.
it shows a capacitor connecting the latch pin to ground
That schematic is simply wrong.
You should only have a cap from each device's Vcc pin to Gnd.
That's maybe the 100'th time i've seen a newbie asking for that cap on that latch pin, and yeah it just plain WRONG!
Who to contact to fix this error on the Wiki ?!
// Per.
I don't know. I've e-mailed The Arduino Team about it a couple of times to no avail.
CrossRoads:
I don't know. I've e-mailed The Arduino Team about it a couple of times to no avail.
I love everything about the arduino, but the Ignorant people behind the website content - that does nothing to correct this - I don't know if i should scream or whatever - It's very bad style.
// Per.
Maybe you need to be like Robert de Niro... "talking italian" 
It is not just a mistake on the schematic, the text talks about it too.
Basically I think what happen was that there was a bit of a supply decoupling issue that was not recognised as such. The cap got put on the latch because they thought it was jitter on the signal. The condition got cured by the parasitic effect of a capacitor acting as a bit of power supply decoupling, but the originators of the tutorial are still convinced that it was the signal quality because what they did cured the problem.
I am horrified that the basics for these official guides are made by people that apparently has no knowledge of electronics :-/
// Per.