[sdiy] is .05 volts low enough to be 0 volts?

[Dave]

Quoting Jon Darby <jdarby at lplizard.com>:

> Howdy again,
>    I'm trying to figure out what is preventing the volume half of my Paia
> Theremax from working and was measing the voltage on pin 1 of the LM339 IC
> and got a voltage of .05 volts. Paia said this should read between 1-7
> volts
> but not 0 or 8.2 volts, which "would indicate trouble in this area" (???).
> Pin 2, which is the Pitch equivilent pin on the IC reads a healthy 6.5
> volts. Is .05 low enough to be considered 0 volts, or should it be a solid
> 0.000 on the multimeter? Thanks a ton.
Nope, not 0.000 
There is always some tolerance needed, otherwise all your digital systems would 
flip 0s and 1s on the noise and hum that is always biking trough town.
I do not know the tolerance for the LM339, but I asume this is more a consumer 
thingy, which correlates with higher voltages to be still considered 0.
Expect something like 0-1 volt is 0, 4-8 volt is 1.
See the specs.
And ohyeah, there is this grey area in which nothing is interpreted as 1 nor 0.*


Dave


* this is already better then humans do, as humans interpretate everything, and 
then come up with obscure semi logic explanations to 'understand' the noise.
So. If you put electrodes on someones neck muscles, say it's for measuring, then 
move his head with your remote control, and then ask 'why did you look away' you 
will get a logical explanation from your test person, like 'oh, just looking if 
my shoes were still there.'
I'd be very happy if the human tresholds would be adjusted a bit. Ideas?


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