NOAHTEC.COM

ALL YOU NEED TO KNOW ABOUT ELECTRONIC REPAIRS

 

What is a crystal ? And how to test it.

   


       

Learn How To Test Electronic Components Like A Professional

 

Crystal are use to keep the frequency of the clock from drifting. If the signal from this clock stops, or is weak, or the pulses begin to vary, the electronic equipments might show intermittent faults or might stop altogether. The microprocessor pins that hold the crystal are usually called OSC IN and OSC OUT as shown in Figure 1 and the frequency is marked on the crystal. Typical examples of crystal oscillator frequency are 3.58MHZ, 4MHZ, 8MHZ, 24MHZ etc.

Testing Crystal
Crystals are quite fragile components because of their construction. Unlike a resistor or capacitor, if you drop one on the ground from a decent height, its 50-50 bet whether it will work again. Testing the crystal is not a breeze either. You cannot just take out your trusty multimeter and plug the crystal in it. In fact, there are three right ways to test a crystal: -

(a) Using Oscilloscope
A crystal produces a sine wave when excited. It is appropriate then, to see a waveform representative of a sine wave on the clock pins. If the clock is not functioning properly, replace the crystal. In most cases this should solve the problem since microprocessors are usually very reliable. Check the crystal with power on.

(b) Frequency Counter
Frequency Counter can be use to check the frequency of the crystal. The reading must be taken when the equipment power is switch “on”. Place the probe of frequency counter to the crystal pin and read the measurement. Be sure that your frequency counter meter has the range that is higher than the crystal frequency you are measuring.

(c) Crystal Checker
With this method, usually the crystal is placed in the feedback network of a transistor oscillator. If it oscillates and the LED is lighten up, this mean that the crystal is working. If the crystal doesn’t work, the LED stays off. Instead of using LED, some other crystal checker uses a panel meter to indicate if the crystal is working or not.

You can download a free crystal project kit at:

www.cs.okanagan.bc.ca/ve7ouc/eng/kc6wdk-mirror/crystaltester.html

If you have a favorite Electronic Repair Technique, a Tip, a Trick or a Gadget that you would like
to share with others, just send it to jestineyong@noahtec.com and i will add it into the electronic 
repair article page. Our electronic repair articles is downloaded several hundred times a month. 
As an appreciation to your contribution towards the free tips that you've sent, we'll include your 
full name, your email address and your website url (if you have one) below each article of yours.
Hence, you'll benefit some free traffic from Noahtech. Thank you very much! 
By the way, if you know of someone who would enjoy this article, please feel free to pass it along to
them. They’ll thank you for it! (If you’re that person and you would like to subscribe, please 
click here) .
Click here to go back to main electronic repair article page.
 
 
 
Google

    

    

    

    

    

 

 

Copyright @ Noahtech Computer Repairing & Services 1996-2005.
All rights reserved