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Failed to get this digital clock kit working :(

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duncan webster11/05/2021 20:24:40
3248 forum posts
56 photos

From the original schematic it appears that the common cathodes are connected to one pin of the chip, so if all 8 segments are lit this pin is required to sink 8* the current of the driver pins. When I've used this type of display there has been a transistor twixt common cathode and chip.

I could well have misread the schematic of course

Edited By duncan webster on 11/05/2021 20:25:02

Michael Gilligan11/05/2021 20:50:07
18080 forum posts
845 photos

Thanks for the good thought, Ian yes

I suspect that the processors may not have been programmed [or are not programmed correctly] but I have no way of checking, and am not much inclined to pursue that side of things.

There were absolutely no instructions, or-logic of-operation, provided with these kits ... so not much educational value. ... But at least they were very cheap.


Michael Gilligan11/05/2021 22:09:32
18080 forum posts
845 photos

Posted by Michael Gilligan on 09/05/2021 21:54:50:


Incidentally, the display is marked HS20401K-30 but I have yet to find its data-sheet.



For anyone who might have these ^^^

This appears to be another model from the same series [but lacking the clock colon]



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