Genuine and possibly dumb question

Why do watch makers advertise "quartz"?

Is it the name of the movement or the actual mineral? Isn't it like one of the cheapest and most abundant minerals? Why is it worthy of advertising?

I never understood this.

@chu

@MelissaBearTrix might be able to answer this.

@davidtheeviloverlord @chu

Inside the watch is a thin crystal of quartz, it vibrates around 32.3 somethings per second, and there is a chip that counts, and then sends a signal to the little motor to take a spin, well rotate

Hugz & xXx

@MelissaBearTrix @davidtheeviloverlord @chu To add on to this, quartz has piezo electric qualities. If you strike it, it generates a charge, but if you run a charge through it it bends, completing a circuit. If you take particularly pure quartz, and shape it very precisely, you can make a highly accurate clock circuit, pretty much the most accurate you can get short of using atomic clocks. During WW2 quartz crystals were considered a military secret by the british, as they were used to tune their radios (for radar, etc). Early computers used them extensively, highest I ever saw was 33Mhz.

By writing "quartz" on the watch, they're advertising that it's pretty damn accurate. Compared to pre-quartz based time measurement.

I know modern devices use MEMS devices -- essentially a very tiny tuning fork made on a silicon chip -- for their low frequency clocks (ballpark of 15khz, the standby clock in a phone will use this), I'm not sure how the 100Mhz + signals are made

@sophie @chu @davidtheeviloverlord

That's all about correct, 32.xxxx is the frequency, and from 30 plus years ago, divisible by 60, I think

Omega also made a 120 mega Quartz and also a dual quartz

Hugz & xXx

@MelissaBearTrix @chu @davidtheeviloverlord 32768, or 2 to the 15th power, a very convenient number for simple computers to work with. I suspect that number is as much selected for the ease of honing in on with cheaper equipment than anything else. If it's off by a few dozen Hz, the device is still accurate to a few seconds per day. Heck it can be off by a few hundred and still be good enough.
@sophie @chu @davidtheeviloverlord @MelissaBearTrix
I want to add here
The reason they choose that frequency is they can run it through a series of very simple latching flip-flop circuits to half the frequency again and again until they get back to one second, and 2^15 is the first power of 2 that most people can't hear

@RnDanger @sophie @chu @davidtheeviloverlord @MelissaBearTrix

That, I didn't know, but totally makes sense. I did the quick mental math and 2^15 would be 32 kHz, above human hearing, and one below that would be only 16, which I could totally hear when younger. Most humans top off around 20k.

Neat!