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Digital alaram clock

rathin2j

New Member
hello,
i have brought a kit of "digital alaram clock".i soldered by my self and it is working properly.i have to submit it in my college.but i dont know how it is working.because what schemetic diagram is there is very confusing.there are two IC's IC2 is CD4541 and IC1 is LM8560.one crystal (of 3.278 MHz)is connected to IC2.but there is not a singal connection which is supplying clock pulse or any type of pulse to IC1.whereas IC1 is clock cum alaram manager cum BCD to 7-segment converter cum 7segment driver,and v all know that clock IC need 1Hz or any type of pulse(which is not provided),then how the IC2 know when to increment the logic state or at what interval it has to give "COLON OUT".please write me an detailed working of this circuit if possible.i can provide u any material u want for proper understanding.i m attaching schemetic diag.,datasheet of both the ics and PCB LAYOUT of both Cu and component side.thanks
 

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ericgibbs

Well-Known Member
Most Helpful Member
hi,
Looked at the circuit drawing, its incomplete also has some errors.
Is this the original drawing that came with the kit.?

EDIT:
look at this image for 'missing' clock. Not shown on diagram

The HEF4541 is set to divide by 65536 from the 3.2768MHz crystal, so the LM8560 is being clocked at 50Hz on pin #25.
 

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rathin2j

New Member
hello sir can u tell me how the pins of IC 4541 r configured?means if v take example of IC7490 than for decade counter pin no:2,3,6,7,10 are shorted and ground where as for devided by 6 counter it's pin no:7,6,10 are grounded and pin 2-9,3-8 are shorted.similarly as v knw that 4541 can b used for 2 raised to 4,8 and 10.so two obtain this all operation?(including 65536 counter).thanks
 

audioguru

Well-Known Member
Most Helpful Member
Why do people who don't "speeky zee English" come here and ask things with horrible spelling and grammar?
 

saturn1bguy

New Member
Why do people who don't "speeky zee English" come here and ask things with horrible spelling and grammar?
My guess is that they don't have such a nice, informative place to go online in their own country. And their poor english skills are likely because they don't speak english.

They're doing their best, mon.
 

audioguru

Well-Known Member
Most Helpful Member
The people who no speeky zee English cannot buy the common parts that are used here. They buy their parts in some kind of "market". Their parts are very old and are not made anymore, some are fake. Their circuits are also very old. Those people are in a different world. Mars?

I don't go to a forum in their foreign country. Because I don't speeky zee their language.
 

saturn1bguy

New Member
They buy their parts in some kind of "market". Their parts are very old and are not made anymore, some are fake. Their circuits are also very old. Those people are in a different world. Mars?
I know, I know, it's a definite struggle for them, isn't it? Here's a parable, AG, I just made it up: Where much is given, much is required...
 

ericgibbs

Well-Known Member
Most Helpful Member
hello sir can u tell me how the pins of IC 4541 r configured?means if v take example of IC7490 than for decade counter pin no:2,3,6,7,10 are shorted and ground where as for devided by 6 counter it's pin no:7,6,10 are grounded and pin 2-9,3-8 are shorted.similarly as v knw that 4541 can b used for 2 raised to 4,8 and 10.so two obtain this all operation?(including 65536 counter).thanks
Hi,
The HEF4541 cannot be configured to give 'powers' of 2 from 2,4 and so on.
There are only 4 division States, look at this attached image.

I have marked the image showing the pins# used and the way the circuit is using them.
Your circuit drawing has errors which if you follow the copper tracks shown on the component side you should be able to correct.:)
Look at the coloured image of the pcb, it should be easier for you to follow.
 

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ericgibbs

Well-Known Member
Most Helpful Member
hello sir,
thank u very much for the help.sorry for the inconvenience caused.
hi,
Its not an inconvenience.:)

Does the reply answer your question and do you now understand the circuit.?
 

quad

New Member
Hello folks,

I have a 110V/60Hz clock radio based on LM8560/TMS3450
which I want to run off a crystal osc and while searching
for info, I found this page (in chinese. you may want to
see a translated version) -

LM8361¡¢TMS3450¡¢TMS1943Êý×ÖÖÓµç·

http://www.hz-qj.com/kkgw/10wj/1013/3450.gif

I know how to generate 50 hz using a 3.2768Mhz crystal using
a CD4060 and a CD4013, but the page above
generates 60hz using a 32768hz watch crystal using a
CD4060 and a CD4013.
Can someone help me understand how this works?

On the same page, the schematic for LM8361 gets a 60hz in
a different way using a 32768hz crystal and a CD4060.
The Q9 output is used as a clock via
a CD4012 dual input NAND gate, using which the clock is inhibited
for 2048 cycles (when the most significant bits are 111X1).
So the clock wiggles 60 times a second ((32768-2048)/512),
but a couple of states are of longer interval, which does not matter.

http://www.hz-qj.com/kkgw/10wj/1013/8361.gif

Thanks!
 

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