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Full Version: HP48 Keyboard Scanning and Electrical Resistance
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The keyboard of the HP48 is scanned as somewhat documented in the available schematics.

Can anyone explain (or direct me to the appropriate links) why the keyboard contact paths have a significant (kilohms) electrical resistance?


Documented in US Patent 5,065,356.

You'll find a copy posted on Eric's site here: PDF of HP Patent 5,065,356

Excellent resource! Thank you very much!