7490 TTL counter newbie question

[Marcel Gonzalez]

I misplaced a horde of examples in which I used to have, and need help for
probably the simplest application. How do I get a 7490 counter to do a BCD
count from 0 to 2 instead of 0 to 10 ?

Thank you,
Marcel

 

[Luhan Monat]

I misplaced a horde of examples in which I used to have, and need help for
probably the simplest application. How do I get a 7490 counter to do a BCD
count from 0 to 2 instead of 0 to 10 ?

Thank you,
Marcel

Lets see. Try a 2 input nand gate from the second and third outputs.
The nand should drive the *reset line.

 

[Luhan Monat]

Lets see. Try a 2 input nand gate from the second and third outputs.
The nand should drive the *reset line.

Ooooops - make that the first and second outputs. When '3' is reached,
reset is generated so it counts 0-2.