Analogue clock circuits?

On 2005-11-15, Mark Harriss <billy@blartco.co.uk> wrote:
Dand wrote:
"Craig Hart" <no@spam.ta> wrote in message news:43788ebd$1@news.eftel.com...

Talking electronics did a digital clock in the 80's that used a bunch of
counter IC's and some transistor logic. keeps 100% perfect time to this
day (gets it's clock off the mains 50 Hz).

This is about the minimum practical integration level for a hobbyist
project, without blowing out the cost to a crazy figure.


Where about are you? My 50Hz strays out and doesn't end up exactally. Over
time my 50Hz clocks end up almost 7 seconds per day off atomic clock via
internet.
Click to expand...
mechanical or electronic? someone said that electronic clocks can be fooled
by glitches, something which could be cured with a decent filter....

A heavily loaded alternator goes low in frequency,
Click to expand...
The guys that run the national grid will run it fast when the load lightens
to compensate.

~20 years ago I was in the cooontrol room at Benmore Hydro station (NZ's
biggest at that time, I think still the biggest one on the grid) they had
two clocks one was synchronised to an atomic standard (WWVH?) the other ran
from the mains. I think at the time I saw it the discrepancy was two seconds

Bye.
Jasen
 
Most 50Hz clocks which run fast have poor filtering, which results in
noise being counted as extra cycles, which cause them to run fast.
Click to expand...
I spoke with someone at enegex and they said 50Hz strays with the load by
+/-0.1Hz. He says the alternators have rotation counts each day and are
almost never the same.
 
"John" <sittingbythepool@internode.on.net> wrote in message
news:437AB6A8.E340F1B1@internode.on.net...
Dand wrote:

Were analogue circuits ever used in Digital clocks ? (aka. transistors
instead of IC's). As far back as I can remember, even in the 80's,
Elementary Electronics magazine used a huge, many-pinned dedicated
clock
chip for a clock project.
Is this possible, or would it require literally hundreds of
transistors?.
As a sidenote, my roommate in College in 79, had a "Digital Clock" that
used
a complicated arrangement of motors, cams, and microswitches to
illuminate
light bulbs in 7 segment displays. It was incredibly complicated, and
well
thought out, but was probably one of the few "Digital" clocks that
hummed
and clicked while it ran.

Awesome.

I built a clock out of nand gates (I scored a pack of 400 quad nand
gates).
What a mess it was. I think it ended up being about 60cm long on 4 way
bread
boards. I needed about 100 capacitors to smooth the power on all the ICs



Were they TTL or CMOS chips

My introduction to electronics was playing with 7400 quad nand gates
and they were a big drain on power supply because they were TTL
devices......
Click to expand...
Nah they were 4000 cmos
 
"Dand"
Most 50Hz clocks which run fast have poor filtering, which results in
noise being counted as extra cycles, which cause them to run fast.


I spoke with someone at enegex and they said 50Hz strays with the load by
+/-0.1Hz.
Click to expand...

** The frequency never really changes, the phase merely drifts up and down
around the centre value.

That is - on a high res frequency meter, the effective AC supply frequency
varies from say 50.1 to 49.9 over a couple of minutes then drifts back
again.


He says the alternators have rotation counts each day and are almost never
the same.
Click to expand...

** All the alternators right across the Eastern half of Australia are phase
locked when in use.

But they can stop and start when taken off line.

So the rev count proves nothing.




.......... Phil
 
Dand wrote:
Most 50Hz clocks which run fast have poor filtering, which results in
noise being counted as extra cycles, which cause them to run fast.


I spoke with someone at enegex and they said 50Hz strays with the load by
+/-0.1Hz. He says the alternators have rotation counts each day and are
almost never the same.
Click to expand...
Most power up my end of the state has to be fed into a local Hydro
station to be "Cleaned up" I don't how this is done but I suspect
they might run one alternator as a motor and pump water back to the
top of the dam to run back through the other turbine and alternator.

A guy I know who has a power station ticket tells me that in the 70's
and 80's their reputation depended on keeping the frequency accurate
through the day in sync with the reference chronometer. These days
the alternators are run at their limits to try and keep up with
modern electrical household loads so they run slower.
 
"Jasen Betts" <jasen@clunker.homenet> wrote in message
news:slrndnler6.2ml.jasen@clunker.homenet...

I've seen digital clocks with "flip-card" displays, driven by a motor
and,
I assume. a mechanism not all that disimilar to those used in
odometers.
Click to expand...

I had one of these when I was a kid. The minutes "cards" looked like a
miniature Rolodex. ;-) A really odd thing about it was that the hours
had a double set of cards (i.e. 1 1 2 2 3 3 4 4). At about 20 minutes
after the hour when the minute would change, the hour "card" would also
flip at the same time exposing the duplicate "card". I never understood
why they did this. Since the hour card had to flip at precisely the
time that the "59" minute card flipped, it wasn't like there was some
unsolvable timing problem that required extra cards. I guess they did
it to just make the hour column Rolodex fuller for easier flipping. It
usually flipped around 20 minutes after the hour, but not always the
exact same minute.
 
"Mark Harriss"

You really don't have a clue do you?.
Click to expand...

** You really don't have a brain - do you Mark ?

It got fried while you were down some hole full of muddy water with a 240
volt powered hot air gun doing cable repairs for Telstra.


BTW

The Turneroid needs someone to bloat his flagging ego.

Time for you to do some more usenet cock sucking.




........ Phil
 
You always switch to insults when caught out bullshitting,
a sure sign you are making up pure crap in a desperate
attempt to seem relevant....

Phase locking.... What utter shit: better watch out now
Phil, there are people here who have worked in the power
generation industry so you can't pretend to know anything
about it.

David comprehensively proved you are full of shit complete
with real examples and all you can do is put your frilly
skirt on.

P.S. I did laugh when I read your pathetic explanations
 
"Mark Harriss"

** As usual top posting and with no context.


You always switch to insults when caught out bullshitting,
Click to expand...

** Shame how I was merely responding to your mindless, fucking insult -
ARSEHOLE !!!
a sure sign you are making up pure crap in a desperate
attempt to seem relevant....
Click to expand...

** Shame how I was merely responding to your mindless, fucking insult -
ARSEHOLE !!!


Phase locking.... What utter shit:
Click to expand...

** It's all shit to a fool like you.


David comprehensively proved you are full of shit complete
with real examples
Click to expand...

** That is a silly and false idea you get to keep - ARSEHOLE.



P.S. I did laugh when I read your pathetic explanations
Click to expand...

** Autistic, fuckwit scum like you laugh at everything.

You really don't have a brain - do you Mark ?

It got fried while you were down some hole full of muddy water with a 240
volt powered hot air gun doing cable repairs for Telstra.


BTW

The Turneroid needs someone to bloat his flagging ego.

Time for you to do some more usenet cock sucking.

The only thing you are skilled at.




........ Phil
 
"Anthony Fremont" <spam@anywhere.com> wrote in message
news:x4Oef.20795$3K6.1620@tornado.texas.rr.com...
"Jasen Betts" <jasen@clunker.homenet> wrote in message
news:slrndnler6.2ml.jasen@clunker.homenet...

I've seen digital clocks with "flip-card" displays, driven by a motor
and,
I assume. a mechanism not all that disimilar to those used in
odometers.

I had one of these when I was a kid. The minutes "cards" looked like a
miniature Rolodex. ;-) A really odd thing about it was that the hours
had a double set of cards (i.e. 1 1 2 2 3 3 4 4). At about 20 minutes
after the hour when the minute would change, the hour "card" would also
flip at the same time exposing the duplicate "card". I never understood
why they did this. Since the hour card had to flip at precisely the
time that the "59" minute card flipped, it wasn't like there was some
unsolvable timing problem that required extra cards. I guess they did
it to just make the hour column Rolodex fuller for easier flipping. It
usually flipped around 20 minutes after the hour, but not always the
exact same minute.
Click to expand...
Maybe thats it .. it was to compensate for inaccurancy in the lining up of
the 2 sets of numbers .. I remember these clocks tho .. great fascinating
things .. had one when i was a kid .. till it stopped running .. motor must
have died or damaged its gears perhaps .. remember pulling it apart and
having these half-number cards scattered EVERYWHERE .. loved it :)

>
 
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