tying 595 outputs together

SgtWookie

Joined Jul 17, 2007
22,230
Are you talking about a 74HC595?

I fail to see why you would want to do such a thing.

Generally, you don't want to tie two outputs together if there is a possibility that one could be high and one could be low. It's OK to do so with open-collector or open-drain outputs though.
 

Thread Starter

mxabeles

Joined Apr 25, 2009
266
hi guys : here is why/
I want to use the 595 outputs as a random "chooser" for the three input pins of a 4051. I could just select three of the 12 or so bits coming out of the stream but I would rather tie 3 bits to each input of the 4051 so there isn't as much dead space if this makes sense.
Schematic attached w/ 3 outputs from 595 tied to each a,b,c of 4051.
Thanks
M
 

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SgtWookie

Joined Jul 17, 2007
22,230
You have multiple text overlaps, so I can't read what the values of your components are.

Don't tie the outputs of the 595 together. Use diodes (like 1N4148,1N914) so that they can only source or sink current, and then use pull-up or pull-down resistors.
 
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