Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [crystal]

Piezo-electric device cut at a specific resonance frequency, mostly used in oscillators.

A crystal is a piezo-electric device cut at a specific resonance frequency. Due to its high Q-factor and high stability crystals are mostly used in oscillators. Also used to create very narrow-band filters. Frequencies range from a few tens of kHz to a few hundred MHz.

Further reading
MSP430 32-kHz Crystal Oscillators, TI Application Report

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How does a quartz crystal work?

Could you explain how a quartz crystal works, maybe with a simple schematics with the essential things ? I know it acts like a kind of stabilizer for an oscillator, but nothing more than that.
Stefano Borini
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Why are 32.786Khz crystal cans soldered to PCB?

Every development board I have ever used that includes a 32.786Khz crystal has always had its can soldered directly to board. What is the reason for this ? Is this to minimize radiated energy from the crystal during its operation (assuming that the…
efox29
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Change in resonant frequency of quartz crystal with atmospheric pressure?

We have a bare quartz crystal and we are measuring its resonance frequency to a very high accuracy (1 ppb). As it cycles between atmospheric pressure and vacuum there appears to be a change in frequency. Could this be because the crystal is being…
Dirk Bruere
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Difference between crystals?

Is there any point in using a big crystal over a smaller one? Apart from the tolerance spec, how come crystal manufacturers have all these different models of crystals from really tiny ones to big ones? I don't think I know the advantage to using a…
cksa361
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How should I select my crystal frequency?

I have seen questions like this that talk about selecting a crystal for UART and I have seen questions like this that mention 32.768 kHz for RTC. But how do I decide the right crystal for my application. At this point I am not sure what UART baud I…
Kellenjb
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How is crystal frequency set?

When you purchase a crystal to use as a clock, the company is asking you exact frequency to set it at. I remember needing a crystal that was 4x the NTSC color carrier and they were asking me how many digit precision I needed. What is the process to…
Thomas
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Does the polarity of this crystal matter?

I am using TXC 7B 16.0 mghz crystal for my design. I just received photo proofs from my PCB assembly house and it appears they soldered this crystal 180.0 degrees reversed. https://www.digikey.ca/products/en?keywords=887-1104-1-ND Edit: the real…
Adam Lee
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Understanding this crystal connection

I have been working on design for which I have a reference schematic. I came across the following crystal setup: I've always seen crystals being connected to two pins on an MCU, like XIN and XOUT with its corresponding capacitors to make up for the…
Big6
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Why parallel resistor for oscillator?

I have a design with a W65C51S ACIA IC, which uses a 1,8 crystal MHz for serial communication. The clock generation example in the datasheet shows an external 1 MOhms resistor in parallel to the crystal. It seems that the crystal doesn´t produce…
Kampi
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Quartz crystals: ESR and how to calculate power dissipation (or drive level)

I am confused about something regarding the quartz crystals. More specifically I cannot understand the difference between the effective or equivalent series resistance (ESR or \$R_e\$), and the motional resistance (\$R_1\$). Below is the typical…
nickagian
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Crystal drive level

I´m working on a new design with MPC5744 (LQFP) microcontroller. As far as I know, the crystal unit drive level could be obtained from the following equation: P=2*Rl*(pifreqVdd*(Cl+Co))2 Taking in to account MPC5744 evaluation board, we have…
Davidtxi
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MEMS oscillator how to wire them and can they replace crystals?

My question is: Can a MEMS oscillator replace a crystal oscillator? If answer is yes, how I can wire them to XIN and XOUT? How should I select capacitor? And since they don't have crystal capacitance load, shout or equivalent ESR in their datasheet…
Yaro
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What's causing my 7.3728 MHz xtal to be unstable?

I'm using a 7.3728 MHz HC-49 crystal with 22pF disc ceramic load capacitors. I'm doing this on a breadboard, but I've had prior experience with using a breadboard for this and it has worked well, so I'm hoping this is not the problem. On the…
Thomas O
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How to check if the crystal's waveform of a circuit is "Normal"?

I have a PCB where I use ECS-240-8-36CKM-TR3 crystal for ADUM4166 isolator and USB2517-JZX USB hub. My circuit works as expected and I want to see and check if the oscillation of the crystals is "fine". The problem is, I can not define "fine". The…
Christianidis Vasilis
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How can I make a crystal oscilate?

I have a 25 Mhz crystal oscillator, and I'm trying to make it oscillate and generate a radio frequency, which then I could view on my SDR waterfall. I have read about crystals, but I still don't get how they work. Can I just hook up then +/- pins…
Dan
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