38.4kHz crystal

Thanks for the reply. I did check with Farnell/Element14 before posting here. But would that be a reliable way of estimating continued availability? If you meant that the quantity in stock at such sources is an indication of a device's popularity, I can understand the logic. But I don't have a good idea of how fast online superstores sell their stuff and what such numbers mean. I'd rather base my decision on how widely used a part is. For example, it's highly unlikely that 32.768 kHz and 27 MHz crystals, 555 ICs, etc will become hard to find any time soon.

It's usually best to find out where it is used, then take a guess of whether this technology will stick around. AFAIK 38.4kHz is a popular clock rate on industrial serial bus systems.

That was my intention. I thought I'd be able to take a short cut by asking here.

I had that impression. 38.4kHz looks like it's associated with standard baud rates of 9600, 19200 etc., but I don't have a clear idea of how commonly a 38.4kHz oscillator is used even in that area of application. Those frequencies just might be more usually derived from clock generators operating at higher or lower frequencies.

Buy a reel.

Cheers

Phil Hobbs

As I said in reply to Joerg, I also associated the number with standard baud rates. What I don't know is how commonly a 38.4kHz clock is generated directly rather than being derived from a higher or lower frequency.

I'm guessing pretty good, because 38,400 Hz is 3 * 10^2 * 2^7 .

My first thought when I recognized the 384 is "baud rate generator."

Cheers! Rich

A 32.768 kHz crystal would be an infinitely better choice.

Otherwise, Statek can make as many as you want of whatever you want.

A typical UART will require at least a clock frequency 16x times the baud rate, so the 38k4 crystal would be good for line speeds up to

A few decades ago 1200bit/s (and 75/1200) modems were common, so such devices might have such a low frequency crystal.

These days it might be easiest to find crystals for 16x115k2 and multiples.

If the crystal really has to be in the LF frequency band (e.g. due to the power consumption) the 32768 Hz is the most common.

There should be a manditory 10 year jail sentence for any further use of a 555.

So go jail half the EEs in China. Good luck with that.

Cheers

Phil Hobbs

That's a firm statement, but why? I like to hear the arguments for that.

petrus bitbyter

There should be a life sentence for anyone with a case of Tripentaphobia.

It's for generating the carrier in a 38kHz IR system. Datasheets of 38kHz IR receivers indicate that the drop in sensitivity at

I've been using IR controls quite a bit recently as part of a larger system. Using a crystal eliminates the need for initial freq adjustments as well as drift, especially with battery-powered sets. Of course, there are ways of getting 38kHz with crystals and ceramic resonators of other frequencies, but this method integrates very well with my designs.

Not to mention for misspelling everyday 4-syllable words.. but I think there might be a market for some kind of little book on the 555-- something that gives simple step-by-step instructions for recreating designs, kind of like a book containing numerous cooking recipes. Not sure what you'd call it though. The Art of 555ery? The Joy of 555s? The Compleat 555? Mrs Beeton's Book of 555 Management?

Forrest Mims had a Radio Shack "Engineering Notebook" version of that, back in the '80s -- it covered most basic applications at the part.

I'd really like to see someone take a book like that and come up with "competing solutions" that are as or more robust and cheaper -- while I can't claim to have designed in a 555 in well over a decade, I think it gets a bad rap at times based on the fact that it often does "just work" and is cheap... and hence there isn't sufficient "snob appeal" to it. :-)

---Joel