need help from a bored smart person

i am trying to make a simple manual operated scoreboard. the attached drawing is made from info that i have copied from the internet. can someone proof read it for me and point out any errors.

74ls192= presettable bcd/decade up/down counter
74ls247= bcd to seven digit decoder/ driver
74ls14= hex schmitt trigger
the signals from the decoder/driver to go to self amplified large 7 segment display numbers.
thank you in advance wayne f.

R3 and R2 are completely wrong. They should be replaced with a real volage regulator.

BrownOut said:

R3 and R2 are completely wrong.

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Hee, hee, when I see something like that, it reminds me that 80+% of the schematics for projects posted on the WEB are crap!

mike ml, you seem to have left the constructive out of constructive criticism.

Wayne,

Whoops, I see now that instead of insulting some anonymous person who posted their pet project on the Web for others to duplicate, I see that I insulted you, who posted a circuit here asking that it be critiqued.

To produce 5V to be used as a logic supply from the 15V primary power source, use a three-legged regulator, such as an LM317 or LM7805. The output from a voltage divider is very dependent on the current being drawn from the tap. With digital logic, the supply current to all of the logic chips is all over the place as the chips switch, so the 5V source needs to be "regulated". Don't forget to bypass the logic chips (Vdd to Vss) using 0.01uF or 0.1uF capacitors (at least three).

Another possibilty: couch the circuit in terms of 4000 or HC series CMOS, which can be operated directly off 15V.

Is this a school project? Is that why it uses old TTL ICs?

I'll try to make a long story short. my goal was to make a (inexpensive) large led score board . being a newbie that can solder i was hoping to find a schematic on the internet that fits my needs order the parts and assemble. i don't recall the exact website were i got the info, but i do remember the author stating that he was confident in his work but did not attempt a working prototype. nor do i remember any dates on the schematics which would probably explain why the parts list include old TTL ICs. it appears that posting it in a forum of experts was a wise choice because you found the problem with the voltage regulator. if that is all that is wrong with it that sounds like an easy fix. i guess this stuff is more complicated than i thought, hats off to you guys.
thanks again.
wayne f

desperate one said:

...i was hoping to find a schematic on the internet that fits my needs order the parts and assemble. i don't recall the exact website were i got the info, but i do remember the author stating that he was confident in his work but did not attempt a working prototype. ...

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Wayne, now I feel better. I was insulting some anonymous web poster; not you.