Is it possible? How did they achieve this in the classical era?

 

Is it possible? How did they achieve this in the classical era?

According to the wiki, it was tuned LC tanks. That’s how cheap AM radios work.

https://en.m.wikipedia.org/wiki/Crystal_oscillator

 

Yes, it is possible. But first you have to define "precise".

 

Is it possible? How did they achieve this in the classical era?

What exactly do you mean by the classical era? Amateur radio transceivers had crystals back in the 1950's

 

What exactly do you mean by the classical era? Amateur radio transceivers had crystals back in the 1950's

And crystal oscillators were used in WW I. (not widely but they existed)

 

I mean what did they use before the invention of Crystal?

 

Yes, it is possible. But first you have to define "precise".

Precise enough to use for a digital clock... I sorta want to build an all transistor clock but do not want to tap into main AC or using crystal

 

I mean what did they use before the invention of Crystal?

https://www.radioworld.com/columns-and-views/the-worlds-first-factorybuilt-transmitters

 

Precise enough to use for a digital clock... I sorta want to build an all transistor clock but do not want to tap into main AC or using crystal

I think an LC tank will give more precision than, for instance, a 555 timer is capable of. Take care in selecting the components to minimize temperature effects and drift. I’m not sure what precision is achievable.

 

I'm looking a a 60 Hz oscillator it very close till i touch it I was just wondering the same how to make it stable

But Mine is using 2 resistors and cap and 2 nand gates It's nice 60 Hz till i touch it. lol

 

Would a sawtooth wave be more stable if it has constant current source?

 

But Mine is using 2 resistors and cap and 2 nand gates It's nice 60 Hz till i touch it. lol

Hmmm... maybe epoxy the whole thing

 

Precise enough to use for a digital clock... I sorta want to build an all transistor clock but do not want to tap into main AC or using crystal

Precision is normally quoted in terms of percent error or drift.
For "precise" timing applications, a quartz crystal oscillator is commonly used.
Accuracy is of the order of 10ppm for a typical crystal oscillator.
1000ppm = 0.1%
100ppm = 0.01%
10ppm = 0.001%
1ppm = 0.0001%

There are 1,036,800 seconds in 12 days.
Therefore a crystal oscillator with 10ppm drift will drift by about 10 seconds in 12 days.

If you want long term accuracy for a time-of-day clock, use the 50Hz or 60Hz line frequency.
The short term stability of line frequency is about ±0.03%. However, the total number of cycles is corrected daily so that long term error is practically zero.

You will discover that any RC oscillator will result in very unsatisfactory time-keeping.

 

Get a time signal broadcast receiver on 60kHz, and decode its output. That way you only have to design and build the display, and your clock will be accurate to seconds for thousands of years.

 

The guy who would come over and tune my father's piano used a set of tuning forks. Ancient battery powered watches used a transistorized "electric" tuning forks. You could hold the watch up your ear and hear the tuning fork.

What's wrong with using quartz?

 

Precise enough to use for a digital clock... I sorta want to build an all transistor clock but do not want to tap into main AC or using crystal

Yeah forget it. Wall clocks require very long term accuracy unless you dont mind resetting it every week or so.
Even regular crystals are not really good enough for wall clocks. You need a temperature compensated crystal oscillator. You can get real time clock boards and chips that do this.

If you use an LC tank you have to temperature compensate it with thermistor(s). It is a royal pain in the neck and it's only as good as you can get it. Probably have to reset the clock once per month.
Might be better off with a pendulum clock (ha ha).

Sync up to WWV.

 

Might be better off with a pendulum clock (ha ha).

Now thats an idea! Use the pendulum to generate clock signal!

 

Now thats an idea! Use the pendulum to generate clock signal!

Terrible idea!

 

How are you going to power the clock?
Is the clock going to be located permanently indoors?
There is so much 60Hz AC signal being radiated that you can pickup the signal without a direct connection.

You can build a solar powered clock. I never completed mine. I had laid out the PCB but never got around to having it fabricated.
It would keep track of solar time and was designed to run for 1000 years without requiring adjustment.

 

I think an LC tank will give more precision than, for instance, a 555 timer is capable of. Take care in selecting the components to minimize temperature effects and drift. I’m not sure what precision is achievable.

I agree. The very first working circuit I built was a CW xmtr modified to emit AM in the 40 and 80 m bands. The VCO had an LC tank with a classic 365 pF variable capacitor. Made it heavy, mechanically (extremely) stable and was furiously shielded. Worked like a gem.