TTL Clock with 7447 7490 and 7400 IC's - Page 5 - Electronic Circuits Projects Diagrams Free

blueroomelectronics · 18th April 2008, 12:56 PM

Quote:

Originally Posted by Pete61

Guess Not!

A can oscillator has four pins.

Thank you all anyway. I will continue experimenting.

The clock is an anniversary present for wife. I have until Aug 1st to complete it.

I'm sure I will will have it all figured out by then.

Thank you all again and take care.

Did she say you have to use 74 series TTL?

RODALCO · 19th April 2008, 09:16 PM

I checked up on the 74160 which is a complete different IC than the 7490 IC's which are cascaded after each other, and are not synchronously driven.

The 74160 needs a bounceless positive edge clockpulse to advance the counting.

You may need to add a buffer or amplifier stage to drive the 74160 counters.

Get some 7490 IC's, they are cheap and will work.

Regards, Raymond

cls_tec · 21st April 2008, 11:55 PM

http://users.otenet.gr/~ATHSAM/frequ..._with_7490.htm

Here is a website that show how to connect the 7490 in all of it's divider configs.

fhnaseer · 25th April 2008, 05:23 AM

Can anyone send me the simplest circuit of digital clock by using IC 74LS90-93, 74LS47 and 7 segment display to my email address "fhnaseer@yahoo.com", send it within one hour, I have to submit it to my teacher, it is a project for my semester, hurry up, within one hour,

Senash1985 · 6th May 2008, 06:44 AM

valid quotes

**Krumlink** · 8th June 2008, 04:59 PM

Quote:

Originally Posted by fhnaseer

Can anyone send me the simplest circuit of digital clock by using IC 74LS90-93, 74LS47 and 7 segment display to my email address "fhnaseer@yahoo.com", send it within one hour, I have to submit it to my teacher, it is a project for my semester, hurry up, within one hour,

Lol you fail.

heres a website to symbolize your failure

Fail Dogs

6502Dude · 8th June 2008, 09:18 PM

Maybe if he didn't spend the semester pulling his wire, he would have had time to draw this simple circuit.

AllVol · 8th June 2008, 11:09 PM

Quote:

Originally Posted by fhnaseer

Can anyone send me the simplest circuit of digital clock hurry up, within one hour,

Here it is!

Oh, darn. Too late.

Anyway, just make up six sets of the attachment, but only one timer, of course.

I'll leave it up to you to figure out how to make it count to 12:59:59.

ece_jm · 20th June 2008, 10:38 PM

nice schematic iyung w, looks interesting.
I just have some questions with your ckt.
1. What is the voltage input of this ckt?
2. Your 74LS47, 74LS08, 74LS32 and other ICs are not connected to Vdd. Do I have to connect it to Vdd and GND for it to work?
3. Does the 1MHz oscillator needs Vdd also for it to function?

Anyone can answer pls. Thanks
http://www.geocities.com/iyung_w/files/24hrs_clock.pdf

shokjok · 12th July 2008, 05:49 AM

For an accurate 60Hz timebase, you can use a 3.579545 MHz crystal with an MM5369, 8-pin IC with discrete components. Eliminate the ten-hour 7490 and 7447 with a 7474 D flip-flop and transistor wired as divide-by-two that is on from 10:00:00 to 12:59:59.
Out of curiosity, how would you set the time on this clock?

audioguru · 12th July 2008, 01:46 PM

The MM5369 has not been made for many years. It needed a supply of at least 9V for its oscillator to work at the 3.58MHz crystal's frequency and its output current was much too low to drive old fashioned TTL. It was good in an accurate low power Cmos clock.

adokilla · 13th July 2008, 12:24 AM

Hello everyone am new to here but am looking forward for a good project that am planning. I would like to build a digital clock. I saw a lot of schematics some of the schematics dont really explain it very well for me since am a newbie in this and still learning. I would really apriciate it if someone showed me step by step on how to do it am currently building something in multisim but am stuck. thats why i would like to start over with someone who could explain step by step thank you very much.

audioguru · 13th July 2008, 12:53 AM

Every year, students ask for the circuit for a digital clock that uses old TTL ICs.

Learn about digital logic then design the circuit yourself. Your teacher expects you to do that, not just copy the circuit from somebody else.

krye · 19th August 2008, 04:09 PM

Here's mine. Works like a charm. 7490's with 7447's for the LEDs.

The daughter board is the bridge rectifier. Also, I attached the schematic for the new one I'm working on. Same as the old, but has a better time setting circuit. The one that I build basically just uses switches to redirect the 1Hz time base into either the seconds, minutes, or hours sections.

The new clock is going to use a crystal so I don't have to bother with the 60 Hz line. I found a neat trick to get an easy, accurate 1 Hz time base for $6....

http://www.josepino.com/circuits/ind...d_timebase.jpc

RODALCO · Today, 04:21 AM

Great ! Job well done krye.

I have been to busy with work to post a schema, and build an other TTL clock for which I have the parts and blue LED 7 segment displays.

Regards, Raymond

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Clock Pendulum Synchronisation	RODALCO	General Electronics Chat	9	4th November 2007 02:23 PM

19th April 2008, 09:16 PM	(permalink)
RODALCO	I checked up on the 74160 which is a complete different IC than the 7490 IC's which are cascaded after each other, and are not synchronously driven. The 74160 needs a bounceless positive edge clockpulse to advance the counting. You may need to add a buffer or amplifier stage to drive the 74160 counters. Get some 7490 IC's, they are cheap and will work. Regards, Raymond __________________ There are more ways to get to Rome. Electricity, Electric clocks, Meters and Trains are great.

21st April 2008, 11:55 PM	(permalink)
cls_tec	http://users.otenet.gr/~ATHSAM/frequ..._with_7490.htm Here is a website that show how to connect the 7490 in all of it's divider configs.

25th April 2008, 05:23 AM	(permalink)
fhnaseer	Can anyone send me the simplest circuit of digital clock by using IC 74LS90-93, 74LS47 and 7 segment display to my email address "fhnaseer@yahoo.com", send it within one hour, I have to submit it to my teacher, it is a project for my semester, hurry up, within one hour,

8th June 2008, 09:18 PM	(permalink)
6502Dude	Maybe if he didn't spend the semester pulling his wire, he would have had time to draw this simple circuit.

20th June 2008, 10:38 PM	(permalink)
ece_jm	nice schematic iyung w, looks interesting. I just have some questions with your ckt. 1. What is the voltage input of this ckt? 2. Your 74LS47, 74LS08, 74LS32 and other ICs are not connected to Vdd. Do I have to connect it to Vdd and GND for it to work? 3. Does the 1MHz oscillator needs Vdd also for it to function? Anyone can answer pls. Thanks http://www.geocities.com/iyung_w/files/24hrs_clock.pdf

12th July 2008, 05:49 AM	(permalink)
shokjok	For an accurate 60Hz timebase, you can use a 3.579545 MHz crystal with an MM5369, 8-pin IC with discrete components. Eliminate the ten-hour 7490 and 7447 with a 7474 D flip-flop and transistor wired as divide-by-two that is on from 10:00:00 to 12:59:59. Out of curiosity, how would you set the time on this clock?

12th July 2008, 01:46 PM	(permalink)
audioguru	The MM5369 has not been made for many years. It needed a supply of at least 9V for its oscillator to work at the 3.58MHz crystal's frequency and its output current was much too low to drive old fashioned TTL. It was good in an accurate low power Cmos clock. __________________ Uncle $crooge

13th July 2008, 12:24 AM	(permalink)
adokilla	digital clock Hello everyone am new to here but am looking forward for a good project that am planning. I would like to build a digital clock. I saw a lot of schematics some of the schematics dont really explain it very well for me since am a newbie in this and still learning. I would really apriciate it if someone showed me step by step on how to do it am currently building something in multisim but am stuck. thats why i would like to start over with someone who could explain step by step thank you very much. Last edited by adokilla; 13th July 2008 at 12:25 AM.

13th July 2008, 12:53 AM	(permalink)
audioguru	Every year, students ask for the circuit for a digital clock that uses old TTL ICs. Learn about digital logic then design the circuit yourself. Your teacher expects you to do that, not just copy the circuit from somebody else. __________________ Uncle $crooge

Today, 04:21 AM	(permalink)
RODALCO	Great ! Job well done krye. I have been to busy with work to post a schema, and build an other TTL clock for which I have the parts and blue LED 7 segment displays. Regards, Raymond __________________ There are more ways to get to Rome. Electricity, Electric clocks, Meters and Trains are great.

6th May 2008, 06:44 AM	(permalink)
Senash1985	valid quotes