Hi all ,

This is my 1st thread and I wanna everyone helps me with ...

I wanna draw a circuit of 24 Hour by using 7490 IC counter to produce suitable outputs for SECONDS, MINUTES & HOURS . Assuming 1 pulse per seond input is available .
Can any one helps me to draw this circuit ??

PLZ >>>PLZ>>>

I'm waiting >>>>>>>>>>>>>>>>>>>>

 

I'd use a micro personally, but heres a 'how to' with a 7490

http://electronics.howstuffworks.com/digital-clock5.htm

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Spency.

PIC Micro's - Your mind is the limit

PIC's and interfacing with other devices - a PIC Basic Guide @ digital-diy.net

 

I've been in that website but it didn't help me alot >>>

I need more explanation ....

 

Look in this forum under TTL clock.
There are various circuits listed with schema's as well.

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Electricity, Electric clocks, Meters and Trains are great.

 

This is a schematic of a secods display that I built for a clock. The rest of the clock consisted of a NTE2061 clock IC. I wanted a seperate seconds display. But since this is seconds the same circuit would work for minutes also. Since the NTE2061 is a PMOS the MPSA13 transistors were used as interface between it and TTL. The current limit resistors for the displays will have to be adjusted as my displays are 4 inch tall and use a 12V supply as the common anode.

Attached Images

seconds.JPG (177.2 KB, 14 views)

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The great thing about electronics is unlimited ways to do the job. The only limit is one\'s imagination. I generally think my way is best.
Show me a different way. I have an open mind.

 

Build a 1Hz crystal oscillator or a 2Hz oscillator and add a d flip-flop to reduce it to 1Hz.

Attached Images

	1 Hz.PNG (7.3 KB, 306 views)
	2Hzclock.jpg (10.9 KB, 7 views)

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