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The article is a nostalgic reminder of when I was first interested in electronics and got interested in quartz resonators for projects. Grinding down old war surplus FT243-style crystals and other types so as to resonate at frequencies I needed was a common practice with hobbyists back then. I used many similar techniques to the same end of removing quartz which raised its frequency. Grinding materials included abras…
Believe or not, when I explained to many non techies how quartz watches work and how any computers’ hardware clocks work in the same principle, they were all surprised how elegant and how efficient the mechanism is. I was also impressed when I first learned about it. True science and engineering beauty.
The article is a nostalgic reminder of when I was first interested in electronics and got interested in quartz resonators for projects. Grinding down old war surplus FT243-style crystals and other types so as to resonate at frequencies I needed was a common practice with hobbyists back then. I used many similar techniques to the same end of removing quartz which raised its frequency. Grinding materials included abras…
That sinking feeling of knowing you've ground off just a bit too much...
And, if you're sneaky, you can add solder.
Obligatory: https://youtu.be/wHenisSTUQY?si=oNOHR9QRCG3GYvf2
Earlier quoted context omitted.
That sinking feeling of knowing you've ground off just a bit too much...
I've just spent the weekend tuning brass reeds from an organ. It sounds like a very similar process, except you can grind both ends of the tongue to raise and lower frequency. And, if you're sneaky, you can add solder.
The quartz crystals themselves were grown with carefully controlled levels of specific impurities (like scandium) in order to reduce their temperature sensitivity.
The article is a nostalgic reminder of when I was first interested in electronics and got interested in quartz resonators for projects. Grinding down old war surplus FT243-style crystals and other types so as to resonate at frequencies I needed was a common practice with hobbyists back then. I used many similar techniques to the same end of removing quartz which raised its frequency. Grinding materials included abras…
> BTW, the mentioning of HF will likely horrify chem-phobic readers I would not say I am chem-phobic, but yes indeed that stood out. HF is nasty stuff, and yes requires some care I suspect. The other details are fascinating, though - the intersection of mechanical, crystallographic, and RF (?) properties of a crystal that you can adjust through abrasives and selection of the cut.
Teflon is not affected by HF, so if you use only vessels of Teflon to hold the HF solution and tweezers made of Teflon for handling anything that you submerge in the solution of HF, it works fine.
Besides using Teflon for anything that is in contact with the HF solution, you must do all work under a hood that evacuates the vapors of HF emitted by the solution, otherwise handling a HF solution would be very dangerous. It is good that gaseous HF is lighter than air, so after being evacuated it will continue to rise in the air, while becoming more and more diluted.
Earlier quoted context omitted.
That sinking feeling of knowing you've ground off just a bit too much...
I've just spent the weekend tuning brass reeds from an organ. It sounds like a very similar process, except you can grind both ends of the tongue to raise and lower frequency. And, if you're sneaky, you can add solder.
Earlier quoted context omitted.
You mean could you get it down to a low enough frequency? Hmm I guess you can get down into audio frequency but maybe the amplitude will be tiny, you probably want a piezo mechanism that will give you more of a rumble.
There are piezo buzzers and beepers, of course.
In the past, audio RC oscillators or LC oscillators were used, with the former being preferred as the latter required too bulky inductors to reach so low frequencies.
Nowadays, it is usually simpler to not use any audio oscillator, but to use some microcontroller that divides the frequency of its clock until reaching the desired audio frequency.