How are crystal oscillators used?

Question

I mean specifically...I know they're piezoelectric etc. etc. but how are they used in a circuit to produce an oscillating output that can, say, trigger the base of a bipolar NPN?

Answer 1

there are many methods.

colpitts oscillator is one.

http://www.geocities.com/raiu_harrison/m...

http://my.integritynet.com.au/purdic/cry...

this link has a lot of info:

http://hem.passagen.se/communication/txo...

When you need a lower frequency, you run a higher frequency crystal and use counter chips to divide the frequency down to where you want it.

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Answer 2

The advantage of crystal oscillators is that they produce a very precise frequency that does not change significantly with minor variations in power supply voltage or temperature.

You should firts check the sdpecifications of the crystal oscillator and see if it's output is TTL or CMOS compatible.  Knowing that, it is relatively eady to construct a simple transistorized buffer circuit.  You can look this up on the internt -- TTL (Transistor-transistor logic) or CMOS (Complementary metal oxide semiconductor) logic.  You will have to use the correct transistor(s) in the circuit -- not all NPN transistor are the same. In fact, there are HUNDREDS of different types, for different uses.

Most crystal oscillators operate in the MHz range (but there are some in the kilohertz range) so to do anything  visibily useful (like flash an LED) you will need other circuts called flip/flops, counters, or dividers.  (Radio Shack used to have good books on these subjects. I wonder if they still do??)

Answer 3

I'd like to ad that they produce waveforms (when used in a well designed circuits) that are very clean. Relatively free of phase and amplitude noise.