Pavel-
Finished!
04/22/2017 at 08:00 • 1 commentThe thing is now complete and working!
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Solution is found!
04/20/2017 at 03:56 • 0 commentsThe humble diode AND was not to blame after all, it was prior wiring that was faulty.
Here are simplified schematics with voltages:
1) original wiring:
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collector of Q1 was wired directly to base of Q2, to achieve second inversion, thus making buffer; simultaneously from the same collector was the tap to the AND gate of decoder, as inverted input. Failed. the solution was to make this into two full-fledged invertors, and after this modification all started to work as it was intended to.2) corrected wiring:
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Problem with output logic levels
04/14/2017 at 04:51 • 0 commentsFor decoder I used simplest diode 4AND logic gates (image), assuming they would work properly, and give +Vcc for high and 0.6V for low.
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Unfortunately, output for HIGH is measly 1.6-1.7V and it is too low for driving display unit.
I am still cannot understand, why is it so.
Simple counter/clock
4-bit counter hooked up to 7-segment display showing succession of hexadecimal digits
collector of Q1 was wired directly to base of Q2, to achieve second inversion, thus making buffer; simultaneously from the same collector was the tap to the AND gate of decoder, as inverted input. Failed. the solution was to make this into two full-fledged invertors, and after this modification all started to work as it was intended to.
