Discrete BCD Counter reset problem

Thread Starter

askingNo123

Joined May 24, 2019
2
Hello, i'm new in electronic and i plan to make discrete bcd counter with T flip flop. Before i make it in real, i tried to make it in pspice. But when i pspice it, i found that second flip flop (which count as 2) does not reset at 10second (When it counts 1010) and because of it, reset occurs every 8 seconds after first reset. i can't find why it happens and how to solve it. Thanks you for your help.

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hobbyist

Joined Aug 10, 2008
892
I don't know how new you are to electronics, that you claim to be, but from your schematic, looks like you've been involved in
design work for quite some time now.

Sorry I don't know how to help you with your request.

However if you ever would like to design a toggle flip flop made from master slave networks all out of transistors, I did a whole youtube series on designing a master slave flip flop all from discrete transistors.

link is here.


then I did a series on converting them to toggle flip flops and designed a binary
to decimal up down counter, that link can be found here.


I just want to share these things, because it seems like nobody wants to design
transistor circuits any more, they want to do all IC system designs now a days,
so when I find someone trying to learn how to do transistor circuits, I like to encourage
them by showing them the possibilities of what can be done with discrete transistors.

That's what my blogs and utube series are in electronics, to show the fun things
that can be done with discrete components.

Please I don't mean to hijack your thread.
 

mvas

Joined Jun 19, 2017
539
Hello, i'm new in electronic and i plan to make discrete bcd counter with T flip flop. Before i make it in real, i tried to make it in pspice. But when i pspice it, i found that second flip flop (which count as 2) does not reset at 10second (When it counts 1010) and because of it, reset occurs every 8 seconds after first reset. i can't find why it happens and how to solve it. Thanks you for your help.
An asynchronous / ripple counter ?
Makes me think your problem is due to a "Race Condition" between the Clock Input & Reset Pin within T Flip-Flop #2 ?
Also, you are using Diodes ( D13 - D16 ) with Q17 to turn OFF these Transistors: Q1, Q6, Q10 & Q14 ? ? ?
 
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