Hi all,
I am trying to create a decade counter by using the below schematic. When I switch on the circuit, by default it displays 5 or 7 (mostly 7) on the display. When I connect pin 14 of the counter to the -ve, I expect it to count the next number. But if it is 7, it changes to 5 and vice versa. But does not change after the first time.
http://www.next.gr/uploads/82-b66141494b.png
Currently I am giving the clock input manually (you can see a black wire hanging from pin 14). I connect this to the ground to give the clock input.
I tested the chips individually and it looks to be working fine. I tested 7447 by giving the -ve input on the pin 3(i think) and the seven seg display showed 8 . Then I connected LEDs on the 4 output of the 7490. I looked for different leds to glow for every time i connected pin 14 to ground and that worked too.
I checked the connections, it looks good. For your expert eyes, do you see any obvious mistakes i have done ?
Note: I do not have 220 Ω resistor handy. So taking up the risk of burning the components, I am proceeding with building the circuit. I hope not using resistor cannot be the reason for the improper display.
With Regards,
S.Sudharsan
I am trying to create a decade counter by using the below schematic. When I switch on the circuit, by default it displays 5 or 7 (mostly 7) on the display. When I connect pin 14 of the counter to the -ve, I expect it to count the next number. But if it is 7, it changes to 5 and vice versa. But does not change after the first time.
http://www.next.gr/uploads/82-b66141494b.png
Currently I am giving the clock input manually (you can see a black wire hanging from pin 14). I connect this to the ground to give the clock input.
I tested the chips individually and it looks to be working fine. I tested 7447 by giving the -ve input on the pin 3(i think) and the seven seg display showed 8 . Then I connected LEDs on the 4 output of the 7490. I looked for different leds to glow for every time i connected pin 14 to ground and that worked too.
I checked the connections, it looks good. For your expert eyes, do you see any obvious mistakes i have done ?
Note: I do not have 220 Ω resistor handy. So taking up the risk of burning the components, I am proceeding with building the circuit. I hope not using resistor cannot be the reason for the improper display.
With Regards,
S.Sudharsan
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