74 series digital circuit of 7490A 74L90 decade computer

Published:2011/3/31 1:27:00 Author:Ecco | Keyword: digital circuit, decade computer | From:SeekIC

7490A, 74L90, 74LS90, 74C90 decade computer Binary frequency and fifth frequency; Door re-zero input and re-set 9 input (used as the complement of applications for BCD9); To utilize the maximum count length of the counter, the input B and output QA could be connected, after input count pulse adds to input A, the out is like the description shown in the menu: output QD connects to input A, and adds the input count to output QA. It will produce input B of frequency square-wave, and get symmetrical frequency count.



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