[sdiy] I'm an idiot, right?

[Peter Grenader]

The National datasheet has the supply pins of the 4050 labeled pin 1 = Vcc
(+ side) and pin 8 = Vss (ground).

My original problem i reported has been fixed.  Allow me to explain:

My application here is a 4516 serial to binary counter into a 4051 mux into
a 4050 buffer.

My problem turned out to be stupidity, channeled in another direction than i
had expected  as my power connections to the 4050's were correct.  The
enigma was their outputs weren't reacting to their input stimuli, they were
staying high regardless of that state.

My assumption was this was a power problem, as I checked, re-checked and
tripled checked my wiring and it was correct.

A sideplot:  The last time i used these chips in this way (sequencer), I
elected to run the stage LEDS in parallel with the inputs of the buffers,
which in turn were driving the stage pots.

The 4051 multiplexer however, does not switch from high to ground  (high
being true) like i thought it did, it switches from high to open. On a scope
you won't know this as it looks like it's going from high to low, while in
actuality its going from high to 'no'.

What I needed to do to get these working (thanks to both John Loffink's and
Rene Schmitz' suggestion) was to hang pulldowns on the 4051 outputs, which
in fact corrected the problem and sinked the 4051 outs to ground when they
weren't live.

I had already tried this, but had selected a value which didn't cut it
(100k) and was resisting trying other vlaues as I knew damn well my last
sequencer doesn't have any and it works perfectly.

But...it did have the stage LEDs connected directly to the 4051 outs and NOT
after the buffers like i am doing this time.  - They in fact acted as pull
downs.  So I had them all along, i just didn't realize it.

So there you go.  A well deserved thanks to John and Rene for coming to my
aid and pulling out the books for me.  I appreciate your comraderie.

best,

Peter




Ken Stone wrote:

> 
>> VSS= +3 thru 15; VCC=ground
> 
> Wrong.
> 
> On a 4050B, pin 1 is VDD in my book - namely the +ve supply.
> 
> pin 8 is Vss and is Ground/0V
> 
> I think the confusion originales from the 4010, an almost identical device
> that has both VCC and VDD for operating between two systems on different
> voltages. I suspect the makers of this data book just used the same art, and
> removed the pin 16 description.
> 
> _______________________________________________________________________
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>