[time-nuts] Bye-Bye Crystals
artgodwin at gmail.com
Tue Mar 14 06:35:05 EDT 2017
For interest, and as part of art project involving crystals. I want to show
a less third-age usage than is common in that space :).Acceleration effect
on frequency may also be featured. No way would I do it for cost or quality.
Like you, I normally use packaged oscillators for most things - though I do
still encounter plenty of the passive crystals on cheap microprocessor
boards. The oscillators may be $1, but I suspect those crystals are 10c.
My first encounters with crystals were probably with the inverter
oscillators of early micros. I gather there's a lot more black magic in
their design than analysis, and as a result they used to have problems
oscillating. The oscillators built into modern micros are a lot better.
I'll probably use a more carefully characterised amplifier if i cut my own
On Tue, Mar 14, 2017 at 8:44 AM, Hal Murray <hmurray at megapathdsl.net> wrote:
> artgodwin at gmail.com said:
> > I'm not after quality - I do have an application in mind but it doesn't
> > to compete with mass production. Just wondering if it's feasible to make
> > something crude that will resonate.
> Are you doing this for fun or ???
> Feasible? Sure. Cheaper? That depends.
> The cost difference between a complete oscillator package and a simple
> crystal is tiny. The osc is often cheaper if you include board space or
> engineering time.
> Is your background digital or analog? Do you want a sine wave or a clock?
> My background is primarily digital. If the chip you are using has 2 pins
> setup to drive a crystal, you can probably get it to run reliably by
> following the data sheet and/or app notes. The usual recipe is 2 tiny caps
> and a big resistor. (big in resistance, not physically big)
> An advantage of using a crystal with the on-chip amplifier that I didn't
> mention last time is that you save the osc power if you power down that
> corner of the chip.
> If you want a sine wave, you are out of my comfort zone. I'd probably look
> in ham radio literature.
> They make logic chips like a 74HCU04, U for unbuffered. One of their uses
> for making oscillators. I've never done it. Try google.
> These are my opinions. I hate spam.
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