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counter using discrete components?

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neazoi

neazoi

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Is there any way to implement the next configuration using just transistors?
It is basically a counter that is used to select the next output by the press of a button. This is used to select bands on a SW radio but it can be used to select the inputs of an audio amplifier sequentially.
It actually sets a voltage on the output, when this output is enabled.

 

Of course it's possible. Before IC came up, even digital computer logic circuits have been built with discrete transistors (and with vacuum tubes before them). Everything can be based on a cross-coupled two transistor flip-flop circuit and diode-transistor logic gates.

P.S.: It's most likely easier to implement a 10 stage ring counter than the original 5 FF johnson counter of CD4017, because it implies more decoding logic. There are also interesting options to design a ring counter with bistable devices, e.g. SCR or unijunction transistors. At ancient days, developers used to design such circuits from the scratch.
 
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yes of course, you can implement it using transistors, after all, all ICs are composed of transistors.
I was trying to find a way not to use so many transistors to "simulate" the behaviour of the chip.

What I am inerested in, is the functionalyti of the circuit. i.e. to set an output on the first key press, then to set another output on the second key press etc...

Have you seen any similar functionality schematic?

I could do it using just a rotary switch, but I like the more electronic way..
 

I was trying to find a way not to use so many transistors to "simulate" the behaviour of the chip.
Click to expand...
That has not been my suggestion. But you can't go with less than 4 flip-flops, using at least two transistors each, and some decoding logic. As I mentioned, a ring counter, using one bistable circuit per decoded output, means possibly less overall effort.

If I remeber right, I have seen similar circuits with first generation of electronical tuned TV.
 
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All right, thank you very much.

I am trying to find a simple solution for electronic switching using less transistors and no relays, but I do not know exactly what to search for :))
 

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