Michael Podgouzov wrote:
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>> Probably, you've burnt it. You didn't specify your chip, but if it
Michael,

It's an 89c4051.

>>worked initially (that is rather odd), that means that the input was in >>LOW state. Naturally, having applied the VCC you burnt it very

The spec says Vcc + 0.5 is ok. Is that being generous? Is it the voltage or the current that's the problem?

>>output in 0). You should better take as a rule never to apply VCC >>directly to anything. As for your application, try to change the >>polarity: you configure the pin you will use as input to 1 and you >>apply ground as active signal.

This sort of logic confuses me - I'm a PLC guy and inputs are forceful and there. Never a concern (usually) w/ sinking vs. sourcing. Is this the common method of measuring inputs - looking for the high-to-low transition with the input "closed" state being to-ground?

Thanks Michael.