Car clock
 

How does my car clock work? It cannot be quartz or radio controlled
as it runs slightly fast. It cannot be synchronous because the supply
is DC. Is there any form of adjustment to get it to run to time?

Car clock
 

In article ,
Scott wrote:
How does my car clock work? It cannot be quartz or radio controlled
as it runs slightly fast. It cannot be synchronous because the supply
is DC. Is there any form of adjustment to get it to run to time?

quartz can run fast - or slow,

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

Car clock
 

On Mon, 22 Mar 2021 19:17:19 +0000 (GMT), charles
wrote:

In article ,
Scott wrote:
How does my car clock work? It cannot be quartz or radio controlled
as it runs slightly fast. It cannot be synchronous because the supply
is DC. Is there any form of adjustment to get it to run to time?

quartz can run fast - or slow,

In what circumstances? I thought it was supposed to be accurate to
one second in so many thousand years. Can the crystal be replaced?

Car clock
 

Scott wrote:
On Mon, 22 Mar 2021 19:17:19 +0000 (GMT), charles
wrote:

In article ,
Scott wrote:
How does my car clock work? It cannot be quartz or radio controlled
as it runs slightly fast. It cannot be synchronous because the supply
is DC. Is there any form of adjustment to get it to run to time?

quartz can run fast - or slow,

In what circumstances?


When cheap crystals and other components are used. Crystals vibrate at a
regular frequency, not an absolute frequency. Which frequency and how
narrow the frequency spread is is what manufacturers pay for.

I thought it was supposed to be accurate to
one second in so many thousand years.

Nothing like that good but some meet the makers specs better than others.

Can the crystal be replaced?

I dare say in theory. How easy that will be to do in any particular car and
whether its worth the trouble is harder to say.

Tim


--
Please don't feed the trolls

Car clock
 

In message , Scott
writes
On Mon, 22 Mar 2021 19:17:19 +0000 (GMT), charles
wrote:

In article ,
Scott wrote:
How does my car clock work? It cannot be quartz or radio controlled
as it runs slightly fast. It cannot be synchronous because the supply
is DC. Is there any form of adjustment to get it to run to time?

quartz can run fast - or slow,

In what circumstances? I thought it was supposed to be accurate to
one second in so many thousand years.

I think you're thinking of rubidium - as in rubidium atomic clock.
https://en.wikipedia.org/wiki/Rubidium_standard

Can the crystal be replaced?

I'm sure it can - but replacing it with a rubidium frequency standard
might prove quite a challenge!
--
Ian

Car clock
 

In article ,
Scott wrote:
On Mon, 22 Mar 2021 19:17:19 +0000 (GMT), charles
wrote:

In article ,
Scott wrote:
How does my car clock work? It cannot be quartz or radio controlled
as it runs slightly fast. It cannot be synchronous because the supply
is DC. Is there any form of adjustment to get it to run to time?

quartz can run fast - or slow,

In what circumstances? I thought it was supposed to be accurate to
one second in so many thousand years. Can the crystal be replaced?

That depends on the quality of the crystal and the control of its operating
temperature. Really high accuracy crystals probably cost as mucha a car.

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

Car clock
 

In message , Chris Hogg
writes
On Mon, 22 Mar 2021 19:41:54 +0000, Scott
wrote:

On Mon, 22 Mar 2021 19:17:19 +0000 (GMT), charles
wrote:

In article ,
Scott wrote:
How does my car clock work? It cannot be quartz or radio controlled
as it runs slightly fast. It cannot be synchronous because the supply
is DC. Is there any form of adjustment to get it to run to time?

quartz can run fast - or slow,

In what circumstances? I thought it was supposed to be accurate to
one second in so many thousand years. Can the crystal be replaced?

I have always thought that some quartz crystal oscillator circuits can
be fine-tuned a few cps either side of the principal frequency, by way
of a simple variable capacitor, and observing the result using an
accurate oscilloscope. I may be wrong, and even if I'm not, I wouldn't
recommend trying it unless you're going to scrap the oscillator anyway
and making a complete balls-up won't matter.

I doubt if many present-day watches actually have a trimmer capacitor,
However, the first one I had (in the 1970s, and bought from a guy at
work who seemed to be able to get his hands on a supply) DID have a
trimmer. With a bit of trial and error, I got the time accurate to a few
seconds a month.
--
Ian

Car clock
 

"Scott" wrote in message
...
On Mon, 22 Mar 2021 19:17:19 +0000 (GMT), charles
wrote:

In article ,
Scott wrote:
How does my car clock work? It cannot be quartz or radio controlled
as it runs slightly fast. It cannot be synchronous because the supply
is DC. Is there any form of adjustment to get it to run to time?

quartz can run fast - or slow,

In what circumstances?

All of them.

I thought it was supposed to be accurate
to one second in so many thousand years.

Not with commercial grade clocks.

Can the crystal be replaced?

Yes, but that wont fix the problem.

Car clock
 

charles brought next idea :
That depends on the quality of the crystal and the control of its operating
temperature. Really high accuracy crystals probably cost as mucha a car.

Or use a normal crystal, but in a temperature controlled oven.

The usual way, is have the clock/watch correct itself once per day, by
receiving MSF.

Car clock
 

"Chris Hogg" wrote in message
...
On Mon, 22 Mar 2021 19:41:54 +0000, Scott
wrote:

On Mon, 22 Mar 2021 19:17:19 +0000 (GMT), charles
wrote:

In article ,
Scott wrote:
How does my car clock work? It cannot be quartz or radio controlled
as it runs slightly fast. It cannot be synchronous because the supply
is DC. Is there any form of adjustment to get it to run to time?

quartz can run fast - or slow,

In what circumstances? I thought it was supposed to be accurate to
one second in so many thousand years. Can the crystal be replaced?

I have always thought that some quartz crystal oscillator circuits can
be fine-tuned a few cps either side of the principal frequency, by way
of a simple variable capacitor,

Yes. But they still vary with temperature.

and observing the result using an accurate oscilloscope.

Nope, not even a frequency counter because they arent that
accurate. You adjust it by seeing if the clock gains or loses.

I may be wrong, and even if I'm not, I wouldn't recommend
trying it unless you're going to scrap the oscillator anyway
and making a complete balls-up won't matter.

It wont work anyway, it will still be temperature sensitive
with commercial grade clocks. You need a temperature
controlled micro oven for the xtal and that's not economic.

You can get clocks that use the gps system to keep accurate
time now and ones that use the mobile phone system.

Car clock
 

After serious thinking %% wrote :
Nope, not even a frequency counter because they arent that
accurate. You adjust it by seeing if the clock gains or loses.

Actually they do calibrate them, against a very accurate and stable
crystal timebase in watch repairers.

Car clock
 

Scott wrote:
On Mon, 22 Mar 2021 19:17:19 +0000 (GMT), charles
wrote:

In article ,
Scott wrote:
How does my car clock work? It cannot be quartz or radio controlled
as it runs slightly fast. It cannot be synchronous because the supply
is DC. Is there any form of adjustment to get it to run to time?

quartz can run fast - or slow,

In what circumstances? I thought it was supposed to be accurate to
one second in so many thousand years. Can the crystal be replaced?

The first 32.768kHz watch crystal that shows up on Farnell has a tolerance
of +/-20ppm:
http://www.farnell.com/datasheets/1718754.pdf

There are 86400 seconds in a day, therefo
86400*(20/1000000) = 1.728 seconds/day
it could be either fast or slow by that amount. That's 10.5 hours/year.

The frequency stabilty is also affected by temperature - for this one that
would be another -20ppm across the kinds of temperature ranges a car might
be exposed to, so the same time skew again if the tolerance happened to
start at -20ppm.

I today dug out an old digital camera that I haven't used for ~5 years. Its
clock was half an hour fast. That's not bad going, all things considered.

Theo

Car clock
 

On 22/03/2021 18:58, Scott wrote:
How does my car clock work? It cannot be quartz or radio controlled
as it runs slightly fast. It cannot be synchronous because the supply
is DC. Is there any form of adjustment to get it to run to time?


What car - how old?

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

Car clock
 

On 22/03/2021 18:58, Scott wrote:
How does my car clock work? It cannot be quartz or radio controlled
as it runs slightly fast. It cannot be synchronous because the supply
is DC. Is there any form of adjustment to get it to run to time?

It is almost certainly quartz crystal and not quite trimmed right. Such
mistakes were very common. One telescope maker fixed it by adding GPS
functionality to reset their RTC to local time. Mine as built from a
previous generation lost 15s/month reliably. They didn't install the
loading capacitors around the crystal to save money ( about 10c ).

It isn't hard to get a quartz clock good to 1ppm or about 30s/year but
only the better manufacturers actually bother to calibrate them.

It is slightly harder for a clock in a car than a watch on someone's
wrist which tends to be temperature compensated by the wearer.

--
Regards,
Martin Brown

Car clock
 

On 22/03/2021 20:03, Chris Hogg wrote:


I have always thought that some quartz crystal oscillator circuits can
be fine-tuned a few cps either side of the principal frequency, by way
of a simple variable capacitor, and observing the result using an
accurate oscilloscope. I may be wrong, and even if I'm not, I wouldn't
recommend trying it unless you're going to scrap the oscillator anyway
and making a complete balls-up won't matter.



They drift by x parts per million per degree celcius hence why with a
crystal if you wanted repeatable accuracy you put it in temperature
controlled environment.

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

Car clock
 

On 22/03/2021 19:41, Scott wrote:
In what circumstances? I thought it was supposed to be accurate to
one second in so many thousand years. Can the crystal be replaced?

Maybe it can. But they trim it until it's "close enough". That's all.

(My watch runs fast)

Andy

Car clock
 

On 22/03/2021 21:38, Harry Bloomfield wrote:
After serious thinking %% wrote :
Nope, not even a frequency counter because they arent that
accurate. You adjust it by seeing if the clock gains or loses.

Actually they do calibrate them, against a very accurate and stable
crystal timebase in watch repairers.

Yebbut a watch runs at a comparatively constant temperature.

--
Cheers
Clive

More Heavy Trolling by Senile Nym-Shifting Rodent Speed!
 

On Tue, 23 Mar 2021 08:31:56 +1100, %%, better known as cantankerous
trolling senile geezer Rodent Speed, wrote:

FLUSH the trolling senile asshole's latest troll**** unread

Car clock
 

On 22/03/2021 18:58, Scott wrote:
How does my car clock work? It cannot be quartz or radio controlled
as it runs slightly fast. It cannot be synchronous because the supply
is DC. Is there any form of adjustment to get it to run to time?

Being a car clock it will be processor based. Some are smart enough to
add or take clock cycles to calibrate the crystal in an automated fashion.

How old is the car? Crystals do age to a certain extent. Cheap ones are
100ppm, ~10s per day. How much is the drift?

For the past decade, most recent radios rely on broadcast stations
encoding the time.
https://en.wikipedia.org/wiki/Radio_Data_System

Car clock
 

On Monday, 22 March 2021 at 22:27:14 UTC, Fredxx wrote:
On 22/03/2021 18:58, Scott wrote:
How does my car clock work? It cannot be quartz or radio controlled
as it runs slightly fast. It cannot be synchronous because the supply
is DC. Is there any form of adjustment to get it to run to time?
Being a car clock it will be processor based. Some are smart enough to
add or take clock cycles to calibrate the crystal in an automated fashion.

How old is the car? Crystals do age to a certain extent. Cheap ones are
100ppm, ~10s per day. How much is the drift?

For the past decade, most recent radios rely on broadcast stations
encoding the time.
https://en.wikipedia.org/wiki/Radio_Data_System

My car seems to use GPS is some form - which is both good and frustrating as it doesn't have built-in satnav.

However, it does not switch to/from summer time. I have switch that on or off manually.

Car clock
 

On Mon, 22 Mar 2021 19:41:54 +0000, Scott
wrote:


On Mon, 22 Mar 2021 19:17:19 +0000 (GMT), charles
wrote:


In article ,
Scott wrote:

How does my car clock work? It cannot be quartz or radio controlled
as it runs slightly fast. It cannot be synchronous because the supply
is DC. Is there any form of adjustment to get it to run to time?


quartz can run fast - or slow,


In what circumstances? I thought it was supposed to be accurate to
one second in so many thousand years. Can the crystal be replaced?


Accuracy is what you pay for. I have had a few £1 rubber watches off
ebay, which either gain or lose 1 minute a day. Probably factory
rejects. So I bought a dozen crystals of specified accuracy for under
£2 the lot, which when installed in the watches rendered them decent
timekeepers.
--
Dave W

Car clock
 

On 22/03/2021 19:17, charles wrote:
In article ,
Scott wrote:
How does my car clock work? It cannot be quartz or radio controlled
as it runs slightly fast. It cannot be synchronous because the supply
is DC. Is there any form of adjustment to get it to run to time?

quartz can run fast - or slow,

there may be a teeny adjustable tuning capacitor inside


--
Of what good are dead warriors? €¦ Warriors are those who desire battle
more than peace. Those who seek battle despite peace. Those who thump
their spears on the ground and talk of honor. Those who leap high the
battle dance and dream of glory €¦ The good of dead warriors, Mother, is
that they are dead.
Sheri S Tepper: The Awakeners.

Car clock
 

On 22/03/2021 20:03, Chris Hogg wrote:
On Mon, 22 Mar 2021 19:41:54 +0000, Scott
wrote:

On Mon, 22 Mar 2021 19:17:19 +0000 (GMT), charles
wrote:

In article ,
Scott wrote:
How does my car clock work? It cannot be quartz or radio controlled
as it runs slightly fast. It cannot be synchronous because the supply
is DC. Is there any form of adjustment to get it to run to time?

quartz can run fast - or slow,

In what circumstances? I thought it was supposed to be accurate to
one second in so many thousand years. Can the crystal be replaced?

I have always thought that some quartz crystal oscillator circuits can
be fine-tuned a few cps either side of the principal frequency, by way
of a simple variable capacitor, and observing the result using an
accurate oscilloscope. I may be wrong, and even if I'm not, I wouldn't
recommend trying it unless you're going to scrap the oscillator anyway
and making a complete balls-up won't matter.

No oscilloscope is good enough - you need a quality frequency counter


--
Of what good are dead warriors? €¦ Warriors are those who desire battle
more than peace. Those who seek battle despite peace. Those who thump
their spears on the ground and talk of honor. Those who leap high the
battle dance and dream of glory €¦ The good of dead warriors, Mother, is
that they are dead.
Sheri S Tepper: The Awakeners.

Car clock
 

"The Natural Philosopher" wrote in message
...
On 22/03/2021 20:03, Chris Hogg wrote:
On Mon, 22 Mar 2021 19:41:54 +0000, Scott
wrote:

On Mon, 22 Mar 2021 19:17:19 +0000 (GMT), charles
wrote:

In article ,
Scott wrote:
How does my car clock work? It cannot be quartz or radio controlled
as it runs slightly fast. It cannot be synchronous because the supply
is DC. Is there any form of adjustment to get it to run to time?

quartz can run fast - or slow,

In what circumstances? I thought it was supposed to be accurate to
one second in so many thousand years. Can the crystal be replaced?

I have always thought that some quartz crystal oscillator circuits can
be fine-tuned a few cps either side of the principal frequency, by way
of a simple variable capacitor, and observing the result using an
accurate oscilloscope. I may be wrong, and even if I'm not, I wouldn't
recommend trying it unless you're going to scrap the oscillator anyway
and making a complete balls-up won't matter.

No oscilloscope is good enough - you need a quality frequency counter

Even that isnt good enough.

Car clock
 

In article ,
charles wrote:
In article ,
Scott wrote:
How does my car clock work? It cannot be quartz or radio controlled
as it runs slightly fast. It cannot be synchronous because the supply
is DC. Is there any form of adjustment to get it to run to time?

quartz can run fast - or slow,

Quite. Depends on how well made it is.

Car electric clocks were around before quartz too. Pure electric were
pretty poor time keepers. Later on came clockwork ones, electrically
wound. They were rather better. Many these days use the car radio RDS
signal.

--
*Heart attacks... God's revenge for eating his animal friends

Dave Plowman London SW
To e-mail, change noise into sound.

Car clock
 

On 22/03/2021 22:05, Clive Arthur wrote:

Actually they do calibrate them, against a very accurate and stable
crystal timebase in watch repairers.

Yebbut a watch runs at a comparatively constant temperature.


On your wrist in all weathers?

Bill

Car clock
 

In article ,
Scott wrote:
On Mon, 22 Mar 2021 19:17:19 +0000 (GMT), charles
wrote:

In article ,
Scott wrote:
How does my car clock work? It cannot be quartz or radio controlled
as it runs slightly fast. It cannot be synchronous because the supply
is DC. Is there any form of adjustment to get it to run to time?

quartz can run fast - or slow,

In what circumstances? I thought it was supposed to be accurate to
one second in so many thousand years. Can the crystal be replaced?

Don't you have any at home? They are normally minutes out each time you
have to re-set for BST, etc.

--
*If vegetable oil comes from vegetables, where does baby oil come from? *

Dave Plowman London SW
To e-mail, change noise into sound.

Car clock
 

In article ,
Chris Hogg wrote:
I have always thought that some quartz crystal oscillator circuits can
be fine-tuned a few cps either side of the principal frequency, by way
of a simple variable capacitor, and observing the result using an
accurate oscilloscope. I may be wrong, and even if I'm not, I wouldn't
recommend trying it unless you're going to scrap the oscillator anyway
and making a complete balls-up won't matter.

Even then, a car is a pretty hostile place, because the temperature varies
so much. Any oscillator needs a constant temperature for best results.

--
*I don't believe in astrology. I am a Sagittarius and we're very skeptical.

Dave Plowman London SW
To e-mail, change noise into sound.

Car clock
 

In article ,
Clive Arthur wrote:
On 22/03/2021 21:38, Harry Bloomfield wrote:
After serious thinking %% wrote :
Nope, not even a frequency counter because they arent that
accurate. You adjust it by seeing if the clock gains or loses.

Actually they do calibrate them, against a very accurate and stable
crystal timebase in watch repairers.

Yebbut a watch runs at a comparatively constant temperature.

Only if you keep it on your wrist at night.

--
*The modem is the message *

Dave Plowman London SW
To e-mail, change noise into sound.

Car clock
 

In article ,
Fredxx wrote:
On 22/03/2021 18:58, Scott wrote:
How does my car clock work? It cannot be quartz or radio controlled
as it runs slightly fast. It cannot be synchronous because the supply
is DC. Is there any form of adjustment to get it to run to time?

Being a car clock it will be processor based. Some are smart enough to
add or take clock cycles to calibrate the crystal in an automated fashion.

How old is the car? Crystals do age to a certain extent. Cheap ones are
100ppm, ~10s per day. How much is the drift?

For the past decade, most recent radios rely on broadcast stations
encoding the time.
https://en.wikipedia.org/wiki/Radio_Data_System

The clock on my car is most odd. Against the pips on FM radio, it always
rolls over the minute bang on. But you can set the time to anything you
fancy. The RDS signal then merely 'locking' it. Suppose it's a decent way
of being able to use it anywhere. RDS might be a pain if you lived on the
edge of two time zones. Luckily, once set correctly, it's very easy to
alter the hour only for BST.

--
*WOULD A FLY WITHOUT WINGS BE CALLED A WALK?

Dave Plowman London SW
To e-mail, change noise into sound.

Car clock
 

On Tue, 23 Mar 2021 11:45:14 +1100, "%%" wrote:



"The Natural Philosopher" wrote in message
...
On 22/03/2021 20:03, Chris Hogg wrote:
On Mon, 22 Mar 2021 19:41:54 +0000, Scott
wrote:

On Mon, 22 Mar 2021 19:17:19 +0000 (GMT), charles
wrote:

In article ,
Scott wrote:
How does my car clock work? It cannot be quartz or radio controlled
as it runs slightly fast. It cannot be synchronous because the supply
is DC. Is there any form of adjustment to get it to run to time?

quartz can run fast - or slow,

In what circumstances? I thought it was supposed to be accurate to
one second in so many thousand years. Can the crystal be replaced?

I have always thought that some quartz crystal oscillator circuits can
be fine-tuned a few cps either side of the principal frequency, by way
of a simple variable capacitor, and observing the result using an
accurate oscilloscope. I may be wrong, and even if I'm not, I wouldn't
recommend trying it unless you're going to scrap the oscillator anyway
and making a complete balls-up won't matter.

No oscilloscope is good enough

Not by itself but if you have an accurate reference frequency and
access to the X amplifier (can you still do that with modern scopes?),
a scope can be a very sensitive indicator.


- you need a quality frequency counter

Even that isnt good enough.

Modern ones are.
https://www.keysight.com/us/en/asset.../5990-6283.pdf

In fact, even the early reciprocal counters from 40 years ago were
more than up to the job.

Car clock
 

On 23/03/2021 00:50, Dave Plowman (News) wrote:
In article ,
Chris Hogg wrote:
I have always thought that some quartz crystal oscillator circuits can
be fine-tuned a few cps either side of the principal frequency, by way
of a simple variable capacitor, and observing the result using an
accurate oscilloscope. I may be wrong, and even if I'm not, I wouldn't
recommend trying it unless you're going to scrap the oscillator anyway
and making a complete balls-up won't matter.

Even then, a car is a pretty hostile place, because the temperature varies
so much. Any oscillator needs a constant temperature for best results.

That might be true of the components surrounding the crystal but
crystals are cut along a plane of the crystal geometry such that
temperature has a small effect on frequency change.

You will often hear of an AT cut:
https://txccrystal.com/term.html

https://www.iqdfrequencyproducts.com...artz-crystals/

Car clock
 

"Dave Plowman (News)" wrote in message
...
In article ,
charles wrote:
In article ,
Scott wrote:
How does my car clock work? It cannot be quartz or radio controlled
as it runs slightly fast. It cannot be synchronous because the supply
is DC. Is there any form of adjustment to get it to run to time?

quartz can run fast - or slow,

Quite. Depends on how well made it is.

Nope, how well its tweaked at manufacture of the clock.

Car electric clocks were around before quartz too. Pure electric were
pretty poor time keepers. Later on came clockwork ones, electrically
wound. They were rather better. Many these days use the car radio RDS
signal.

Car clock
 

Clive Arthur laid this down on his screen :
On 22/03/2021 21:38, Harry Bloomfield wrote:
After serious thinking %% wrote :
Nope, not even a frequency counter because they arent that
accurate. You adjust it by seeing if the clock gains or loses.

Actually they do calibrate them, against a very accurate and stable crystal
timebase in watch repairers.

Yebbut a watch runs at a comparatively constant temperature.

That very much depends on how you wear a watch, I wear the same watch
night and day, even in the bath and shower. Some people change their
watch to suit their mode of dress.

Car clock
 

Fredxx formulated on Tuesday :
That might be true of the components surrounding the crystal but crystals are
cut along a plane of the crystal geometry such that temperature has a small
effect on frequency change.

You will often hear of an AT cut:
https://txccrystal.com/term.html

...and they all change frequency a little, as they age and all need a
frequency trimmer to enable them to be adjusted to an exact frequency.
The trimming components are as critical as the crystal, if best
accuracy is aimed for.

Car clock
 

Dave Plowman (News) has brought this to us :
Many these days use the car radio RDS
signal.

Mine does - always correct ;-)

My landline phone system maintains the time and date, for logging any
calls and displays the time when 'parked'. It doesn't get used very
much and I notice it drifts quite a lot. That syncs itself with any
incoming or outgoing call.

Car clock
 

Does it make any noise?
Brian

--

This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"Scott" wrote in message
...
How does my car clock work? It cannot be quartz or radio controlled
as it runs slightly fast. It cannot be synchronous because the supply
is DC. Is there any form of adjustment to get it to run to time?

Car clock
 

Not a lot of detail, analogue or digital, and incidentally, I had a so
called radio clock that in some places in the house ran fast since it lost
lock to its signal which apparently came from Germany.
Brian

--

This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"charles" wrote in message
...
In article ,
Scott wrote:
How does my car clock work? It cannot be quartz or radio controlled
as it runs slightly fast. It cannot be synchronous because the supply
is DC. Is there any form of adjustment to get it to run to time?

quartz can run fast - or slow,

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

Car clock
 

On 23/03/2021 00:45, %% wrote:


"The Natural Philosopher" wrote in message
...
On 22/03/2021 20:03, Chris Hogg wrote:
On Mon, 22 Mar 2021 19:41:54 +0000, Scott
wrote:

On Mon, 22 Mar 2021 19:17:19 +0000 (GMT), charles
wrote:

In article ,
Â*Â* Scott wrote:
How does my car clock work?Â* It cannot be quartz or radio controlled
as it runs slightly fast.Â* It cannot be synchronous because the
supply
is DC.Â* Is there any form of adjustment to get it to run to time?

quartz can run fast - or slow,

In what circumstances?Â* I thought it was supposed to be accurate to
one second in so many thousand years.Â* Can the crystal be replaced?

I have always thought that some quartz crystal oscillator circuits can
be fine-tuned a few cps either side of the principal frequency, by way
of a simple variable capacitor, and observing the result using an
accurate oscilloscope. I may be wrong, and even if I'm not, I wouldn't
recommend trying it unless you're going to scrap the oscillator anyway
and making a complete balls-up won't matter.

No oscilloscope is good enough - you need a quality frequency counter

Even that isnt good enough.

Yes, it can be

It simply needs a better internal oscillator, temerature compensated
than the one it is testing and enough electronics to display very small
differences. and a stable environment and regular calibration.

Needless to say, they are not cheap.




--
€œI know that most men, including those at ease with problems of the
greatest complexity, can seldom accept even the simplest and most
obvious truth if it be such as would oblige them to admit the falsity of
conclusions which they have delighted in explaining to colleagues, which
they have proudly taught to others, and which they have woven, thread by
thread, into the fabric of their lives.€�

ۥ Leo Tolstoy

More Heavy Trolling by Senile Nym-Shifting Rodent Speed!
 

On Tue, 23 Mar 2021 11:45:14 +1100, %%, better known as cantankerous
trolling senile geezer Rodent Speed, wrote:


No oscilloscope is good enough - you need a quality frequency counter

Even that isnt good enough.

In auto-contradicting mode again, you subnormal senile sociopath? BG

--
John addressing the senile Australian pest:
"You are a complete idiot. But you make me larf. LOL"
MID: