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TTL Clock with 7447 7490 and 7400 IC's

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I have seen various threads with TTL requests regarding how to and build a TTL clock or counter with discrete components.

As I have build around 7 of these clocks in the early 1990's and these TTL, LED clocks are still going strong I decided to have a look in my archives and post the basic diagramme for it.

I have learned building them also by trial and error and from various sources like TTL Cookbook (Don Lancaster) and Digitale klokschakelingen (Herbert Bernstein) written in Dutch origin Germany.

As i like the old TTL technology and with carefull and accurate ratsnest wiring a very accurate clock can be build at very low cost but labour intensive but that doesn't matter for a hobby.

Important is the decoupling of every 74xx IC with a 100 nF disc capacitor.
I omitted these in my earlier clocks and later addition of these was painful but not impossible.

The numbers 6 and 9, can be made with tails by adding an extra 7408 AND gate to drive a BC 547 to sink the A and D segment when these have to light up.
A 74247 IC has those functions built in but i have never seen one of those.
IC's.

Attached is the basic schema which works well and i'm more than happy to give more info to potential TTL clock builders. Also i'm happy to post more photo's if required.

**broken link removed**

:eek:hm: :mu: :eek:hm:

Can I make the same clock with CMOS CD4xxx series chips?

CD4059-divide-by-60 for 60hz(mains Freq.) in, and 1hz out
CD4511-BCD 7-seg display driver
CD4029-Up/Down BCD counter
CD4011-as NAND gates
and what chip do I need to to replace your SN7413 chip?

Help is greatly appreciated!

-Ben
 
CMOS clock

For the 7413 chip a 4093 can be used as that has the Schmitt trigger built in.
The 7413 makes square waves and takes the noise out of the reference sine wave.

Probably not a bad idea to start a new thread for a CMOS clock to keep all information together pertaining to the CMOS clock project.
 
For the 7413 chip a 4093 can be used as that has the Schmitt trigger built in.
The 7413 makes square waves and takes the noise out of the reference sine wave.

Probably not a bad idea to start a new thread for a CMOS clock to keep all information together pertaining to the CMOS clock project.

Thanks!

I don't know all the different CD4xxx series chips.
I might start a new thread for a cmos clock sometime soon.

-Ben
 
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I am in the process of designing a TTL clock. One of the features I would like to add is the blinking 12:00 you see when you first power up a digital clock. Right now I am at a stand still on how to do this. Any suggestions or ideas would be greatly appreciated. Thanks is advanced.
 
7490 clock buttons

can anybody tell me how to add buttons for minutes and hours in th 7490 ic based clock in which both mod 6 and mod 10 counter are constructed from 7490 ics,,,itsa 24 hour clock......plz explain it with schematic.............
 
can anybody tell me how to add buttons for minutes and hours in th 7490 ic based clock in which both mod 6 and mod 10 counter are constructed from 7490 ics,,,itsa 24 hour clock......plz explain it with schematic.............
In the 70'ies (36 years ago) I used old fashioned 74xx and 74LSxx logic ICs until I tried CD4xxx and 74HCxxxx Cmos ICs. I threw away my TTL cookbook and bought a Cmos cookbook and used Cmos ever since. I think old fashioned teachers still use old fashioned TTL logic ICs.

36 years ago every school kid made a TTL clock. Now every school kid makes a programmed PIC clock. EXCEPT NOT IN 3RD WORLD COUNTRIES.
 
Look at the schema at the beginning. by adding NPN transistors at point F.
 
Could you please share with me your schematic. I need it for my project.
Thank you in advance. ^^
 
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All the info is in this thread. Only parts required.
 
Hi raiz
Attached is an image from the 12 counter.
I posted this in an other thread at this forum too.
Glad that you got it working all right.
I prefer the 24 hour set up for clocks anytime but it is easy to convert to 12 if you like.
I hope that you decoupled all the IC's with a 100 nF capacitor across the 5 volts IC supply points.

**broken link removed**

I'm getting a hard time in this, it counts like this: 01-02-03-04-05-06-07-08-09-20-21-22 then back to 01..... pls. help :D
 
Check the 7400 connections. That decodes the 24 hours. Have you connected it to the correct A and B inputs ?
 
I disagree, If one uses a cmos version and a good quality film capacitor the
the frequency can be adjusted to exactly 60Hz and it will be very stable. I say a cmos version as it can have much higher value of timing resistors to bring the frequency down to 60Hz.

we built a Master Clock system for ships using a hermetically sealed oscillator (running in an insulated oven at a constant temperature), and even at 6ppm error, you could still see up to 15 seconds of error a month... a 555 is not any where near this stable or accurate, even most watch crystals have more error than this, most crystals are rated in the % and ppm/°C. Even the 3.58MHz colorburst crystal used in a color tv is reset into sync at the start of every line sent.

The most stable and accurate time base will be derived from line frequency as it is adjusted (usually around midnight) to be a 60 HZ average over the day. A 555 may look like it's giving you 60Hz, but any accumulation of timing periods (like a clock) will show a very large error in as little as a week, or even a day.
 
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