Oscillator installation orientation

[Michael Chare]

Would an elecrical oscillator such as the small ones shown in this picture mind which way round they are installed?

[tabbypurr]

no

NT

[The Other John]

No.

[Andrew Gabriel]

No. There's probably one in your wristwatch.

Temperature stability does have a small impact on the frequency. For highly stable operation, they are sometimes installed in a small oven so they can be heated to a constant temperature.

[The Natural Philosopher]

If it's a quartz crystal, no.

If it's a whole circuit to make an oscillator, yes of course, it will have a +ve and -ve, and generally an output too.

that photo is not of 'oscillators' of course. It's of crystals. They are

*part* of an oscillator.

[tabbypurr]

2 terminal oscillators are certainly possible. But they're just crystals.

NT

[Harry Bloomfield]

Michael Chare used his keyboard to write :

The two pins are reversible (no polarity) and the physical orientation doesn't matter either.

[Michael Chare]

Thanks for all the replies. I could not find any markings and I am now sure that I have not put it in the wrong way round.

[Martin Brown]

Installed where? I have never seen a crystal that wasn't marked on the outside of the can with the operating frequency or a code for same.

If you said what the application and frequency was it would be possible to suggest a simple circuit to test it independently.

Watch xtals at 32768Hz are easily blown to bits unless you use a lower drive power but usually survive a few days on the higher power. Most other things will stand a fair amount of abuse from logic chips.

Some are tetchy about starting or are off frequency if the right load capacitor network isn't placed around them. Older Meade telescopes are an example where the RTC keeps appalling time and has to be reset almost every session. They fixed it by adding a GPS function!

[The Natural Philosopher]

I've never seen a crystal oscillate on its own.

[tabbypurr]

FWLIW I expect they do, moving back and forth due to environmental vibration. With high Q they can't build up much movement, but it's not zero.

NT

[The Natural Philosopher]

Bells don't ring without bell ringers.

[tabbypurr]

You've never carried them around then. They tinkle.

NT

[The Natural Philosopher]

Then *you* are the bell tinkler.

[Martin Brown]

Neither have I. Increasingly though oscillator modules are sold rather than bare crystals but they tend to have 4 or even 6 connections.

The canonical two terminal oscillator is the old bimetallic strip winker for car indicators of old where the current flow heats the strip up and breaks the circuit then cools and remakes. Likewise for a magnetic based buzzers and traditional solenoid ding-dong doorbells.

[Adrian Caspersz]

"put them in upside down and the electrons will fall out..."

[Dave Plowman (News)]

You'd call that an oscillator?

[The Natural Philosopher]

All of those have outputs that are not electrical though. Light or sound.

[tabbypurr]

That's one way to miss the point.

NT

[The Natural Philosopher]

well you missed it first. My point was that oscillators need energy sources, and therefore passive components like bells or crystals are not oscillators unless they have a source of energy, be it battery, bell ringer, or jerking around in your trousers.

And its very rare to have a two terminal *active* electrical device as in general you need two wires for supply, and one for the output, and if there is an input one for that too.

A car flasher is not an oscillator, until it is connected to a bulb., Then it is a two terminal device BUT the output is the light. Same for a buzzer. Except that's sound.

And a bell without a bell ringer isn't an oscillator either.

Only when its being jerked around does it ring.