COLPITTS 1 To 20 MHz Crystal Oscillator

COLPITTS 1 To 20 MHz Crystal Oscillator

Colpitts 1MHz To 20 MHz Crystal Oscillator Circuit

This is a simple Colpitts crystal oscillator for 1 to 20 MHz,

Colpitts 1MHz To 20 MHz Crystal Oscillator Circuit

R1 220kΩ
R2 1kΩ
C1 82pF
C2 0.001µF
C3 100pF
C4 0.01µF
C5 0.001µF
Q1 2N3904
XTAL1 CRYSTAL (1 to 20 MHz)

This can be easily made from junk-box parts (provided that a crystal is handy).

2N3904 NPN Transistor General Purpose Amplifier

2N3904 NPN Transistor Pin Configuration

Please send your ideas, which are very important for our success…

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17 comments on “COLPITTS 1 To 20 MHz Crystal Oscillator
  1. Copied your osc. circuit. Colpitts. I intend to use it in a receiver 455 Khz BFO and hopefully make the crystal series capacitor variable to “pull” the frequency through part of the audio range. Should be more stable than the standard L-C layout.

  2. Advantage says:

    So could I plug the 50mV output of this into an op amp and amplify it? What may be a good amplifier to do that with?

  3. weelium says:

    i m having some problem in producing a 1mhz oscillator, if i use the circuit that provided here, can i manage to make it?.. and, i have no idea about it, and in an absolutely troubled situation.. thank you..

  4. almat says:

    This schematic is not universal for broad frequency range because it`s purpose is for the natural frequency of the crystal.It can be pulled down only with frequency dividers and also needs precise calculation for different crystals.

  5. Baruch Atta says:

    @almat – just substitute a parallel coil and cap for the crystal and you will have a variable frequency oscillator.

  6. Parth Sane says:

    Can the frequency be doubled? I understand this is for the natural frequency. I want to use the second harmonic of 3.579MHz crystal to build a 7MHz frequency source to test my other circuit. Any ideas on how to do that?

    • anirudh says:

      since the q factor of the crystal is very high, the circuit tuned for boosting the natural oscillations of the crystal can not be used for second harmonic of the crystal. May be some other frequency multiplying techniques will work. Also, if you see the frequency expression of the crystal, a large variation in the load will result in the frequency deviation of several tens of PPM. Thus, this circuit will not help you to get the multiples of the resonant frequency of the crystal.

  7. Wilbert says:

    Thanks to my father who informed me concerning this weblog, this webpage is in fact awesome.

  8. Manjit says:

    Dlp projector bypass 5pin

  9. Dreamer says:

    Is it important to use 2N3904 transistor?
    I’ve build this circuit with BC547 and looks like it works OK, but I don’t know if it could be better.

    Thank you

  10. dani r safii says:

    why’d we use that value of capacitors? do you have any calculation or something?

  11. Mario says:

    I found it better to remove C2, and make C1=1nF, C3=10nF, and C5=100pF, all other being the same.

  12. Todd says:

    Thanks for the circuit. C2 seemed to double my frequency (though with smaller amplitude of 50mv. Removing V2 left my Vamp the same as my Vdc, and the frequency matched my crystal’s frequency.

  13. Nigel says:

    Replace C3 with a variable cap or preset to enable adjustment of the XTAL frequency and fine tuning. Good as a driver stage before buffer and final amp and bandpass filters for a simple low power TX or Direct Conversion RX.

  14. Thandanani says:

    I Want to design an oscillator circuit which will provide an output frequency below 4MHZ, can i use the above circuit?

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