4-bit BCD counter w/LED's

[Viper5]

Hello. I am new to this forum and to electrical projects. I would like to build a 4-bit BCD counter w/LED's with FF's. I have been doing some research into what parts I need and I understand the general concept of what I need, but it's finding the correct resistors and LED's and switches that gets me confused. I may also consider building an up/down counter instead. From what I understand, there is the 4510 which already has the BCD part built in and even has the up/down. As for my first idea, I think what I need is 2x SN54107's (to replace 4 FF's), 1x CD4073B (triple 3-input AND for A&B with A&B&C), and 1x SN7400 (quad 2 input NAND for B&D reset). I hope I am talking in the right lingo here. I would also like to understand how to make a clock. It may be cool to get it at 1Hz like a clock. I have been trying to figure out if I could just also make momentary switch to activate the pulse or does it have to be a certain frequency? Or maybe I could have another switch which controls if I want to use the clock (sync) or not clock (async). As I said before, I am confused as to what LED's I would need.

I found a website which shows something that seems close to what the more complicated version would look like, but they have capacitors and resisitors and I have no idea how they figured out that they needed them and to what value. The website is here: **broken link removed**. They also added some 4093 chip which somehow makes the clock. Again I have no idea how that works.

Any help with my questions would be greatly appreciated. Thanks.

 

[Dr_Doggy]

sounds like you know what your after, I'd suggest skipping all that and getting a micro controller & demoboard for your projects, a good software learning tool is free GREAT COW graphic BASIC, all for 60$

this way instead of all the wiring and rewireing you just put down some code, and can change it up as you want, and will save you $$ in the long run if you are getting in to digital projects

 

[jeyes56]

if your led is not too big, then you may disregard using a resistor and your supply may be within 3.5-5 volts.
the connection depends on what FF your'e using, since you specify it to be SN54107 (JK FF), i assume that you understand how JK FF works, to do this, you also need to have a knowledge in making a truth table

Prev Next JA KA JB KB JC KC JD KD
0000 0001 0 x 0 x 0 x 1 x
0001 0010 0 x 0 x 1 x x 1
...... .........
1001 0000 .........


something like that....