can you make a quartz crystal vibrate?

[the guy]

if you take an ordinary quartz crystal and apply a voltage to it, will it vibrate?

 

if not, how do you make it oscillate? and will it be enough that you can feel it?

[swansont]

Yes you can make it vibrate; what you want to do is have an amplifier circuit with feedback, where the potential across the crystal is part of a capacitor, so the RC circuit has a resonance. That way you can tune the resistor (or a second capacitor) so that the voltage oscillates at the same frequency as the crystal. There are a lot of different circuit designs that will do this.

 

You probably can't feel the DC displacement, but it will buzz if the frequency is high enough — buzzers use piezoelectric transducers. The displacement is small, but you can stack many of them together. The stack actuators I'm familiar with have a travel of less than 1 mm.

[Ophiolite]

As a geologist my natural approach would be to hit it with a hammer.

[the guy]

thankyou, could you give an example of a simple circuit design?

 

and haha ophiolite

 

also, what happens if alternating current is used?

[swansont]

Google on crystal oscillator circuit. There are many types.

[the guy]

ok thanks

[timetes]

if you take an ordinary quartz crystal and apply a voltage to it, will it vibrate?

 

if not, how do you make it oscillate? and will it be enough that you can feel it?

 

 

and can you do it from a distance? like...remotely? shut it on and off? it may be a silly question but are these crystals in voting machines? I know they use them in humans for medical purposes........

[swansont]

and can you do it from a distance? like...remotely? shut it on and off? it may be a silly question but are these crystals in voting machines? I know they use them in humans for medical purposes........

You could turn the circuit on and off remotely. Any electronics with its own processor will have a clocking circuit.

[TonyMcC]

Yes you can make it vibrate; what you want to do is have an amplifier circuit with feedback, where the potential across the crystal is part of a capacitor, so the RC circuit has a resonance. That way you can tune the resistor (or a second capacitor) so that the voltage oscillates at the same frequency as the crystal. There are a lot of different circuit designs that will do this.

 

You probably can't feel the DC displacement, but it will buzz if the frequency is high enough — buzzers use piezoelectric transducers. The displacement is small, but you can stack many of them together. The stack actuators I'm familiar with have a travel of less than 1 mm.

 

Did you mean "tune an INDUCTOR (or capacitor)"? A crystal is usually accurately cut to oscillate at a given frequency or one of its harmonics. That manufactured frequency can be changed a certain amount with a tuned circuit - but only by so much. The resonant frequency of a tuned circuit is 1/(2*pi*(SQR(L*C))) Hz. I have never experienced an oscillator circuit that was tuned to a different frequency by changing resistance.

[timetes]

could that be why so many people today are hearing ringing or humming in their ears? and Ophio's comment.....lolol ....why hitting it with a hammer..lol.... is that what a bug is made out of lol.....when they say if walls could talk...lol

 

last question:.....how would anyone detect one...... like if your going thru an airport....could one be detected in a human going thru a scanner.....or that scanner affect that person....like shutting it off or vibrating it....especially if its a heart monitor......

 

Did you mean "tune an INDUCTOR (or capacitor)"? A crystal is usually accurately cut to oscillate at a given frequency or one of its harmonics. That manufactured frequency can be changed a certain amount with a tuned circuit - but only by so much. The resonant frequency of a tuned circuit is 1/(2*pi*(SQR(L*C))) Hz. I have never experienced an oscillator circuit that was tuned to a different frequency by changing resistance.

 

 

since the crystal oscillates at its given frequency or harmonics..........what would happen if someone with one of these crystals was sitting watching a movie with surround sound with all the vibrations included in that moving........ wouldnt or couldnt that circuit be affected by that frequency?

[swansont]

Did you mean "tune an INDUCTOR (or capacitor)"? A crystal is usually accurately cut to oscillate at a given frequency or one of its harmonics. That manufactured frequency can be changed a certain amount with a tuned circuit - but only by so much. The resonant frequency of a tuned circuit is 1/(2*pi*(SQR(L*C))) Hz. I have never experienced an oscillator circuit that was tuned to a different frequency by changing resistance.

 

Yeah, brainfart. R doesn't affect the resonance.

[timetes]

ok..... like in a remote control........i picked up a universal remote for an old tv...... i had to keep repeating the signal till it picked up the tv signal number. So is that remote a signal generator or a frequency generator? Why would a magnet repel the wave or frequency . Wondering if the oscillation would change the repelling?

 

Whats the difference from a RF and a microwave frequency? is it the heat? again wondering if the oscillation causes the heat? Just a question because these vibrations i've been getting......and zaps......... i was holding the remote while on the cell phone and the remote vibrated and i dropped it......... what would cause that.

 

One last question: can a rf wave cause an electrical wave current?......kind of like two electrical wires causing a magnetic wave.

[Stevekir]

On 6/16/2011 at 9:16 PM, swansont said:

Yes you can make it vibrate; what you want to do is have an amplifier circuit with feedback, where the potential across the crystal is part of a capacitor, so the RC circuit has a resonance. That way you can tune the resistor (or a second capacitor) so that the voltage oscillates at the same frequency as the crystal. There are a lot of different circuit designs that will do this.

 

I have no problem with tuning the RC circuit to the frequency of the crystal. But how is it that the crystal used vibrates at the fixed speed of 32,768 vibrstions/sec. Is this number decided by nature? If so it is a remarkable coincidence that Providence has provided a number capable of being divided by 2  15 times  (or any other suitable number to replace the 15) to give a pulse of once per second. There is an infinite range of numbers in the world (such as 32,769 to (2 x 32,768-1)) that would not give this exact result and if Nature had "chosen" one of these, a quartz crystal could not be used.

Could the answer be that by manufacturing the crystals (by the million), they could be tested for the few that had the correct property? A time-consuming task.

What's the answer to this conundrum please?

Thanks.

[Mordred]

Quartz crystals has  piezoelectric properties due to its electric dipole structure. Quartz has a natural structure however many ceramics can be manmade. The frequency of resonance is determined by the same structure. However different frequencies can be generated by different dipole arrangements.

https://en.wikipedia.org/wiki/Piezoelectricity

Edited January 28, 2019 by Mordred

[Strange]

48 minutes ago, Stevekir said:

But how is it that the crystal used vibrates at the fixed speed of 32,768 vibrstions/sec.

The frequency is determined by the size and the "cut" of the crystal.

Crystals are manufactured with a range of different frequencies. 32kHz is useful, as you say, for real time clocks. Microcontrollers typically use crystals with a frequency of 10MHz to 15MHz - this is multiplied up internally to the microcontroller to provide the different frequencies used by the bus, processor, memory, etc. Other systems use clocks of different frequencies.

Although crystals provide a stable frequency reference, the frequency can also be adjusted over a small range by changing the load capacitance in the circuit.

[swansont]

1 hour ago, Stevekir said:

I have no problem with tuning the RC circuit to the frequency of the crystal. But how is it that the crystal used vibrates at the fixed speed of 32,768 vibrstions/sec. Is this number decided by nature? Thanks.

No, it's how big the crystal is, and how it is cut, mainly.

 

edit: xpost with Strange 

9 minutes ago, Strange said:

 Crystals are manufactured with a range of different frequencies. 32kHz is useful, as you say, for real time clocks. Microcontrollers typically use crystals with a frequency of 10MHz to 15MHz - this is multiplied up internally to the microcontroller to provide the different frequencies used by the bus, processor, memory, etc. Other systems use clocks of different frequencies.

We use 5 MHz in our fountain clocks, since that's convenient — many of our signals are at 5 MH (making the clock comparisons simple), and it's easily multiplied up to other frequencies we use.