Flip Flop Reset?

[Jarod_C]

I'm thinking of getting this chip HERE, but I don't think it has a reset. If output control goes high I think it'll just stop count right? So there's no reset? Can some one look over the pdf for me to see if I'm right. It's allready ordered so I'm kicking myself right now. I wasn't thinking.

Anyone know a good place to order TTLs in DIP package? I'm trying to make a resettable binary counter.

 

[Roff]

I'm thinking of getting this chip HERE, but I don't think it has a reset. If output control goes high I think it'll just stop count right? So there's no reset? Can some one look over the pdf for me to see if I'm right. It's allready ordered so I'm kicking myself right now. I wasn't thinking.

Anyone know a good place to order TTLs in DIP package? I'm trying to make a resettable binary counter.

Your analysis is not correct, but the 374 is not a good choice to make a binary counter. You would need to add more parts, and even then, you could only make a synchronously resettable counter (can only be reset when clock occurs).
What are you going to use the counter for? We should be able to help you choose a better part(s).

 

[Hayato]

Is it not better to use an binary counter? Like 74161?

 

[Jarod_C]

I'm making staging lights like at the drag races, I'm not using a pic because I'm not able to yet(more learning). Here's the schematic I'm making. As you can see it's not done, and only half there. I'm changing the binary to a BCD counter. I'm having trouble finding the seven segment decoder though. I have seven segment displays picked out that will work great. Give me your thoughts so far.

oh yea, merry chirstmas

 

[Hayato]

That's not a BCD counter, that's a Johnson Decade counter.

There are a few things.
With 5V, the 4017 output is 4.6V with 1mA maximum. A led will be bright enough with 10 ~ 15 mA.
So, connect the LEDs on the transistors collectors, in series with a 470 ohm resistor, each.
And change the base resistors, use a 39k ~ 47k resistor, with a transistor with hfe = 100. (eg.: BC548).

Why did you add those diodes in the 7408?

 

[Roff]

The circuit you posted is for a drag racing Christmas tree, not 7-segment. Are you planning to use a numerical countdown instead of a Christmas tree?

 

[Jarod_C]

Like I said it's not finished. The BCD, and seven segment isn't even shown, that will be for the reaction times. I didn't show a lot of resistors, to much time, and the diodes are for the 4017, I heard it shorts the other outputs. Ah, i'll just put the gate after the transitors. I just had a duh moment.

Speaking of the 4017 does anyone know of a datasheet that shows a schematic of it not just the logic.

Sorry about the confusion, i'll try to clean up the schematic, and post it again.

I think i'm going to ditch the bcd(not shown), and just light one of two lights to see who was fastest.

 

[Hayato]

Instead of using those diodes, it's more safe to use the green led pin, inverted.

 

[Jarod_C]

I changed the schematic some.

If you had two buttons, and you had two LEDs and wanted to find witch one pushed first how would you do that. so you have SW1 SW2, and LED1 LED2 but you only wanted to light one led to show who pushed first how would you do that?

If i get this working i'll make sure to post video, thanks for helping.

 

[Hayato]

For example, if car 1 would violate first, then red light 1 would turn on and the whole circuit would freeze?

 

[Hayato]

How do you want them to be lit?
For example (- off, O on)
A)
---
O--
-O-
--O

B)
---
O--
OO-
OOO

 

[TexasTech]

Hey im not sure if you still have this schematic for the racing tree but i'v been looking for this for a project, but I have used the 7474 dual chips and its not working right. Im not sure on what to do so if any one of you can help me.