Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Quartz crystal under external magnetic field?

Status
Not open for further replies.

neazoi

Advanced Member level 6
Joined
Jan 5, 2008
Messages
4,115
Helped
13
Reputation
26
Reaction score
15
Trophy points
1,318
Location
Greece
Activity points
36,882
What will happen if I bring a magnet close to a quartz crystal when operating as a resonant element in an oscillator circuit?

Will the frequency of the crystal slightly change?
Will it's Q be affected?
What other parameters will be affected?

I am asking for crystals having a metal enclosure, as well for these that have a ceramic/organic or glass enclosure.
 

A crystal vibrates with <10uW of energy. ,exceeding 50uW will damage it. Being a piezo effect device, make it sensitive to stray capacitance, C coupled noise and perhaps long tracks can be senistive to current pulses with H field noise.

But not DC E Fields or H fields. The crystal is not magnetically sensitive, only vibrationally and thermally sensitive at,its resonant points.

- - - Updated - - -

Magneto-Piezo electric effects are found in exotic materials like Cr2O3 not quartz.
 
I suspect that there will be a small effect on the frequency, though not enough for you to measure as it will be swamped by more obvious effects. One could easily argue that any paramagnetic material within a few inches of the crystal and the oscillator circuit will have some effect on the frequency.
Frank
 

According to this article, effect on frequency shift may be negligible if we consider the intrinsic standard error associated to crystal frequency: **broken link removed**
 

According to this article, effect on frequency shift may be negligible if we consider the intrinsic standard error associated to crystal frequency: **broken link removed**


Interesting article. My conclusion is same as before.

Non-ruggedized AT cut crystals are not magnetic. But mechanically ruggedized plate holders on crystals such as SC cut crystals used for stratum clocks >$400 or cheaper versions using ruggedized AT cut crystals suffer from the use of magnetic properties of the spring and plate unless using copper alloy.

The springs attenuate acoustic vibration but can be sensitive to magnetic modulation and thus all these types are sealed in vacuum Faraday cage i.e. metal box from supplier and often include regulated oven for OCXO function and improved performance. These tests were done , without this shield, were done to explain how much this affect occurs to eliminate bad choice in ferromagnetic springs.

I have many years of experience testing Crystals to extreme environments from 100g drop, 50g spin, 15g vibration , thermal shock and magnetic fields to backup my opinions using Vectron Products and others.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top